When play on server, local or not - mob drop tab don't work, it just empty even with vanilla mobs.

In singlplayer - all work fine

Try diff version from 1.18.1 alpha release to current latest 1.18.2 release

What is the exact version of JER/JEI you are running? Any other mods involved?
Can you share a client log from when you join a server?

jei-1.18.2-9.7.0.193
JustEnoughResources-1.18.2-0.14.1.167

That's now, but this issue was here in every 1.18 versions i play, start from 1.18.1

many other mods involved, ATM7 modpack

[11:00:38] [Thread-60/ERROR]: An error occurred building event handler java.lang.NullPointerException: Cannot invoke "java.lang.ClassLoader.loadClass(String)" because the return value of "java.lang.Thread.getContextClassLoader()" is null at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-5.0.3.jar:5.0.3+70+master.d7d405b] at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:88) ~[modlauncher-9.1.3.jar:?] at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:120) ~[modlauncher-9.1.3.jar:?] at cpw.mods.modlauncher.TransformingClassLoader.maybeTransformClassBytes(TransformingClassLoader.java:50) ~[modlauncher-9.1.3.jar:?] at cpw.mods.cl.ModuleClassLoader.readerToClass(ModuleClassLoader.java:110) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.lambda$findClass$16(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.loadFromModule(ModuleClassLoader.java:226) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.findClass(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.loadClass(ModuleClassLoader.java:132) ~[securejarhandler-1.0.3.jar:?] at java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[?:?] at net.optifine.GlErrors.getGlError(GlErrors.java:67) ~[?:?] at net.optifine.GlErrors.isEnabled(GlErrors.java:56) ~[?:?] at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:169) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Thread-60/ERROR]: An error occurred building event handler java.lang.NullPointerException: Cannot invoke "java.lang.ClassLoader.loadClass(String)" because the return value of "java.lang.Thread.getContextClassLoader()" is null at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-5.0.3.jar:5.0.3+70+master.d7d405b] at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:88) ~[modlauncher-9.1.3.jar:?] at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:120) ~[modlauncher-9.1.3.jar:?] at cpw.mods.modlauncher.TransformingClassLoader.maybeTransformClassBytes(TransformingClassLoader.java:50) ~[modlauncher-9.1.3.jar:?] at cpw.mods.cl.ModuleClassLoader.readerToClass(ModuleClassLoader.java:110) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.lambda$findClass$16(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.loadFromModule(ModuleClassLoader.java:226) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.findClass(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.loadClass(ModuleClassLoader.java:132) ~[securejarhandler-1.0.3.jar:?] at java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[?:?] at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:190) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Thread-60/ERROR]: An error occurred building event handler java.lang.NullPointerException: Cannot invoke "java.lang.ClassLoader.loadClass(String)" because the return value of "java.lang.Thread.getContextClassLoader()" is null at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-5.0.3.jar:?] at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-5.0.3.jar:5.0.3+70+master.d7d405b] at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:88) ~[modlauncher-9.1.3.jar:?] at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:120) ~[modlauncher-9.1.3.jar:?] at cpw.mods.modlauncher.TransformingClassLoader.maybeTransformClassBytes(TransformingClassLoader.java:50) ~[modlauncher-9.1.3.jar:?] at cpw.mods.cl.ModuleClassLoader.readerToClass(ModuleClassLoader.java:110) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.lambda$findClass$16(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.loadFromModule(ModuleClassLoader.java:226) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.findClass(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] at cpw.mods.cl.ModuleClassLoader.loadClass(ModuleClassLoader.java:132) ~[securejarhandler-1.0.3.jar:?] at java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[?:?] at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:214) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured, at: alphaTestRef [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured_lit (gbuffers_textured), at: gbufferModelView [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured_lit (gbuffers_textured), at: gbufferModelViewInverse [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured_lit (gbuffers_textured), at: gbufferProjectionInverse [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured_lit (gbuffers_textured), at: shadowProjection [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured_lit (gbuffers_textured), at: shadowModelView [11:00:38] [Thread-60/ERROR]: OpenGL API ERROR: 1282 (GL_INVALID_OPERATION error generated. No active program.) java.lang.Exception: Stack trace at com.mojang.blaze3d.platform.GlDebug.m_84038_(GlDebug.java:180) ~[?:?] at org.lwjgl.opengl.GLDebugMessageCallbackI.callback(GLDebugMessageCallbackI.java:39) [lwjgl-opengl-3.2.2.jar%2346!/:build 10] [11:00:38] [Render thread/ERROR]: [Shaders] OpenGL error: 1282 (Invalid operation), program: gbuffers_textured_lit (gbuffers_textured), at: isEyeInCave [11:00:40] [Render thread/INFO]: Loaded 1 waypoints from C:\Users\Mikhail\Documents\curseforge\minecraft\Instances\All the Mods 7 - ATM7 - 1.18.2\journeymap\data\mp\~Minecraft_57af5298~ab76~4f29~ac90~864b8cebb715\waypoints [11:00:40] [Render thread/INFO]: Mapping started in C:\Users\Mikhail\Documents\curseforge\minecraft\Instances\All the Mods 7 - ATM7 - 1.18.2\journeymap\data\mp\~Minecraft_57af5298~ab76~4f29~ac90~864b8cebb715\overworld. Memory: 8000MB total, 4866MB free [11:00:42] [Render thread/WARN]: attempting to load item into food list that is no longer edible: minecraft:air (ignoring in case it becomes edible again later) [11:00:44] [Render thread/INFO]: [Shaders] Framebuffer created: dfb [11:00:44] [Render thread/WARN]: Image not found: alexsmobs:textures/entity_icon/mimic_octopus.png [11:00:44] [Render thread/WARN]: Image not found: occultism:textures/entity_icon/marid.png [11:00:44] [Render thread/WARN]: Image not found: minecraft:textures/entity_icon/villager/immersiveengineering:anvil.png [11:00:44] [Render thread/WARN]: Image not found: alexsmobs:textures/entity_icon/crocodile_0.png [11:00:44] [JM-texture-3/WARN]: Can't bind texture: java.lang.IllegalStateException: Rendersystem called from wrong thread at com.mojang.blaze3d.systems.RenderSystem.m_187556_(RenderSystem.java:183) ~[client-1.18.2-20220404.173914-srg.jar%23319!/:?] at com.mojang.blaze3d.systems.RenderSystem.m_187555_(RenderSystem.java:161) ~[client-1.18.2-20220404.173914-srg.jar%23319!/:?] at net.minecraft.client.renderer.texture.AbstractTexture.m_117963_(AbstractTexture.java:66) ~[client-1.18.2-20220404.173914-srg.jar%23319!/:?] at journeymap.client.render.texture.TextureImpl.m_117966_(TextureImpl.java:209) [journeymap-1.18.2-5.8.2-forge.jar%23198!/:1.18.2-5.8.2] at journeymap.client.render.texture.TextureImpl.m_117963_(TextureImpl.java:310) [journeymap-1.18.2-5.8.2-forge.jar%23198!/:1.18.2-5.8.2] at net.minecraft.client.renderer.texture.TextureManager.m_118495_(TextureManager.java:106) [client-1.18.2-20220404.173914-srg.jar%23319!/:?] at journeymap.client.render.texture.TextureCache.getTexture(TextureCache.java:211) [journeymap-1.18.2-5.8.2-forge.jar%23198!/:1.18.2-5.8.2] at journeymap.client.render.draw.DrawMarkerStep$1.call(DrawMarkerStep.java:103) [journeymap-1.18.2-5.8.2-forge.jar%23198!/:1.18.2-5.8.2] at journeymap.client.render.draw.DrawMarkerStep$1.call(DrawMarkerStep.java:96) [journeymap-1.18.2-5.8.2-forge.jar%23198!/:1.18.2-5.8.2] at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) [?:?] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [?:?] at java.lang.Thread.run(Thread.java:833) [?:?] [11:00:44] [Render thread/INFO]: [CHAT] §eJourneyMap:§f Нажмите [§bX§f].

client log on join mostly spam Optifine GL errors, nothing about JER

Is this still an issue?

Is this still an issue?

on latest ATM7 - yes, 1.18

don't check 1.19 yet, idk about this version

Could you please post a full client log from launch until after joining a server (gist or pastebin).

latest.log
Here it is, there is bunch of render errors spam, but nothing about JER

I'm also experiencing this in my modpack, any way I can help?

We are having this issue in FTB Inferno as well,
JEI version: jei-1.18.2-9.7.1.255
JER Version: JustEnoughResources-1.18.2-0.14.1.171

Still an issue in 1.19.2
Tested with all the mods listed below, none showed mob drops while connected to a server
Server had all the same mods installed, only vanilla mob drops were shown
Forge 43.1.43
jei-1.19.2-forge-11.3.0.271
JustEnoughResources-1.19.2-1.1.0.179
blue_skies-1.19.2-1.3.20
DivineRPG-1.9.5
The_Undergarden-1.19.2-0.8.2
twilightforest-1.19-4.2.1421

Still an issue. I'm using Fabric 1.19.2.

However, it's not the tabs are empty, they just don't exist at all when playing on a server, while fine on singleplayer.

Updated server and client to JustEnoughResources-1.19.2-1.2.2.200.jar, and now on top of modded mobs not showing vanilla mobs no longer show on server

I figured out what's causing this! I have datapack for all mob heads drop - and this break JER on server Probably any mod that add mob drops via vanilla datapack methods can cause this, so maybe JER need some rewriting

What mod is it that's causing this problem?

I figured out what's causing this! I have datapack for all mob heads drop - and this break JER on server Probably any mod that add mob drops via vanilla datapack methods can cause this, so maybe JER need some rewriting

What mod is it that's causing this problem?

Exactly as i say - datapack moremobheads, not the mod
It's from vanillatweaks

I suppose that some other mods can cause this issue - if they use vanilla datapack methods for modification loot tables from mobs

I figured out what's causing this!
I have datapack for all mob heads drop - and this break JER on server
Probably any mod that add mob drops via vanilla datapack methods can cause this, so maybe JER need some rewriting

Still has the same issue on the All The Mods 7 modpack (1.18.2).
JEI: 10.2.1.1004
JER: 0.14.1.171

The Dungeons Chest menu is empty as well, and the rest of the menus don't take into account modded items

Seeing this issue as well (and missing ore gen graphs) on a custom pack for 1.18.2.
JEI: 10.2.1.1005
JER: 0.14.1.171
Forge: 40.2.10

If I launch MC, load a single player save, go back to the main menu, and THEN connect to the server, JER will work. (for a while, at least)
Don't know if it matters, but I did notice that diydata is true in the config (even if I delete it and let it re-create it), but I don't see a world-gen.json getting created anywhere.