Got the following error today on 1.16.5 running 1605.2.0-build.3.jar. Caused the server to crash. Server restart fixed it, but figured I'd report the issue anyway :)
Server thread/ERROR] [minecraft/MinecraftServer]: Encountered an unexpected exception
java.lang.NoSuchMethodError: moze_intel.projecte.gameObjs.container.TransmutationContainer.(ILnet/minecraft/entity/player/PlayerInventory;Lnet/minecraft/util/Hand;)V
at dev.latvian.mods.projectex.block.StoneTableBlock$ContainerProvider.createMenu(StoneTableBlock.java:98) ~[projectex:1605.2.0-build.3] {re:classloading}
at net.minecraftforge.fml.network.NetworkHooks.openGui(NetworkHooks.java:226) ~[forge:?] {re:classloading}
at dev.latvian.mods.projectex.block.StoneTableBlock.func_225533a(StoneTableBlock.java:76) ~[projectex:1605.2.0-build.3] {re:classloading,pl:runtimedistcleaner:A}
at net.minecraft.block.AbstractBlock$AbstractBlockState.func_227031a(AbstractBlock.java:640) ~[?:?] {re:mixin,xf:fml:forgeendertech:coremod,pl:runtimedistcleaner:A,re:classloading,xf:fml:forgeendertech:coremod,pl:mixin:APP:supplementaries.mixins.json:AbstractBlockMixin,pl:mixin:APP:immersiveengineering.mixins.json:coremods.AbstractBlockStateMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.management.PlayerInteractionManager.func_219441_a(PlayerInteractionManager.java:338) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:mixins.artifacts.json:item.diggingclaws.PlayerInteractionManagerMixin,pl:mixin:A}
at net.minecraft.network.play.ServerPlayNetHandler.func_184337_a(ServerPlayNetHandler.java:958) ~[?:?] {re:mixin,pl:accesstransformer:B,xf:fml:astralsorcery:reach_set_server_entity_interact,xf:fml:astralsorcery:allow_entity_interaction,xf:fml:hammerlib:coremodone,re:classloading,pl:accesstransformer:B,xf:fml:astralsorcery:reach_set_server_entity_interact,xf:fml:astralsorcery:allow_entity_interaction,xf:fml:hammerlib:coremodone,pl:mixin:A}
at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.func_148833_a(SourceFile:36) ~[?:?] {re:classloading}
at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.func_148833_a(SourceFile:10) ~[?:?] {re:classloading}
at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) ~[?:?] {re:mixin,re:classloading}
at net.minecraft.util.concurrent.TickDelayedTask.run(SourceFile:18) ~[?:?] {re:classloading}
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23) ~[?:?] {re:mixin,re:computing_frames,re:classloading}
at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:734) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:159) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:717) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:711) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213161_c(SourceFile:127) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:697) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240802v(MinecraftServer.java:646) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240783a(MinecraftServer.java:232) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:betterendforge.mixins.json:MinecraftServerMixin,pl:mixin:A,pl:runtimedistcleaner:A}
at java.lang.Thread.run(Unknown Source) [?:1.8.0_311] {}
Got the following error today on 1.16.5 running 1605.2.0-build.3.jar. Caused the server to crash. Server restart fixed it, but figured I'd report the issue anyway :)