Observed on the 23/4/20 via analytics for 1.15-1.40:

Stacktrace:
java.lang.NullPointerException at bassebombecraft.network.packet.RemoveEffect.lambda$handle$0(RemoveEffect.java:84) at net.minecraftforge.fml.network.NetworkEvent$Context.enqueueWork(NetworkEvent.java:215) at bassebombecraft.network.packet.RemoveEffect.handle(RemoveEffect.java:76) at net.minecraftforge.fml.network.simple.IndexedMessageCodec.lambda$tryDecode$3(IndexedMessageCodec.java:124) at java.util.Optional.ifPresent(Unknown Source) at net.minecraftforge.fml.network.simple.IndexedMessageCodec.tryDecode(IndexedMessageCodec.java:124) at net.minecraftforge.fml.network.simple.IndexedMessageCodec.consume(IndexedMessageCodec.java:157) at net.minecraftforge.fml.network.simple.SimpleChannel.networkEventListener(SimpleChannel.java:79) at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:212) at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:204) at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) at net.minecraftforge.fml.network.NetworkInstance.dispatch(NetworkInstance.java:84) at net.minecraftforge.fml.network.NetworkHooks.lambda$onCustomPayload$0(NetworkHooks.java:74) at java.util.Optional.map(Unknown Source) at net.minecraftforge.fml.network.NetworkHooks.onCustomPayload(NetworkHooks.java:74) at net.minecraft.client.network.play.ClientPlayNetHandler.func_147240_a(ClientPlayNetHandler.java:1868) at net.minecraft.network.play.server.SCustomPayloadPlayPacket.func_148833_a(SCustomPayloadPlayPacket.java:59) at net.minecraft.network.play.server.SCustomPayloadPlayPacket.func_148833_a(SCustomPayloadPlayPacket.java:11) at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23) at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103) at net.minecraft.client.Minecraft.func_195542_b(Minecraft.java:898) at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:554) at net.minecraft.client.main.Main.main(SourceFile:204) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:56) at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) at cpw.mods.modlauncher.Launcher.main(Launcher.java:65)

Resolved with commit d196ee2.