General Info

• I can reproduce this issue consistently in single-player
• I can reproduce this issue consistently in multi-player
• I have searched for this issue previously and it was either (1) not previously reported, or (2) previously fixed and I am having the same problem.
• I am crashing and can provide my crash report(s)
• I am using the latest version of the modpack

Modpack version

1.0.2

Java version

Java(TM) SE Runtime Environment (build 1.8.0_74-b02)

Modpack Launcher Used

CurseForge

Memory Allocated

8 GB

Minecraft World Environment

Single Player

Misc Client Info

• Optifine Installed
• Shaders Installed

Server Java Version

No response

Server Operating System

No response

Misc Server Info

• Sponge or Non-Vanilla Forge Server

Issue Description

After running the game AFK over night, hostile mobs no longer spawn on dreadful dirt.
Spawners still appears to work.
After quitting the game and starting it again, hostile mob spawning is back to normal.

I believe that I've observed this situation for a long time, and that it's not really tied to dreadful dirt, as I had trouble getting hostile mobs to spawn in a mob farm similar to TheOnlyBentley's setup in your YouTube series.

Additional Information

Here is a screenshot of my hostile mob farm when it's running as expected:

Here's a video showing mob spawn rates before and after logging in.
Notice that I do also have a blaze spawner above the mob farm, so don't count blazes.
There's a clear difference in spawn rates after logging back in.

This one is tough to get to the bottom of. I've run mob farms for days at a time and not noticed the spawns slowing down. It's hard to know what the actual cause is based on the information you gave. When this happens, the log might show some helpful information to pinpoint the issue.

Is it possible you could share you world folder since that would be the easiest way to replicate your issue?

Also can add something here. I built a mob farm at y=2 and automated it with a spike and two fans but no dreadful dirt yet. It seemed to work fine, but after a couple hours it stopped working. Even reloading does nothing. It is like the area is now out of mobs. Added my world too.
First World.zip

Thank you for taking a look. I'll share my world folder the next time I notice the issue.

@Th3Doctorr I think your issue is not the same as the initial reported problem. Your spawner is not an optimal setup for mob spawns.

For you to increase mob spawns, I would encourage you to increase the depth of your room. Right now it's 1 wide. I'm able to increase spawns in your world by extending to 3 depth.

Also, with the way spawning works, having a platform above your mob spawner is going to slow things down. It would be better if there was no platform above since the spawn checks will check up to the highest block in that column. If your mob farm roof is the highest block in terms of Y level then the checks can happen faster and mobs should spawn quicker. It will spawn even faster if you were to build you mob farm higher above your main base. We've added a mod into that pack that alters how mob spawning happens. If you want some more information you should check the mod description: https://www.curseforge.com/minecraft/mc-mods/spawn-normalization

@Darkosto, thanks for that info. I thought it was just vanilla spawns.