I am running Arclight 1.16.4-1.0.11-SNAPSHOT-feb567a. Surprisingly enough it initializes all plugins (and mods?) just fine but then it starts spamming errors at insane rate. Tested on 0.18.60

Clean from any other plugins and mods, fresh generated world
debug.log
latest.log

With production plugins, mods and worlds
2021-01-07-5.log

Do you have any progress regarding this issue? @jediminer543

This would be an absolute life saver, mods like this are almost essential on any modded server with more than 15/20 players.

I think that the issue does not come from Arclight but from the bukkit compatible server (spongeforge).

I think that the issue does not come from Arclight but from the bukkit compatible server (spongeforge).

Spongeforge isn't compatible with bukkit/spigot plugins. It's compatible with sponge api plugins.
@Dum4G you should wait for @jediminer543 response, cuz I don't have the knowledge yet to help you. The only thing I can say is that every thread is generating a crash report. It gets crashed at this stage net/minecraft/world/server/ServerTickList.tick and it's doing "updating neighbors" (chunks??? I don't know what it can be to be honest)

Best Regards
Kubi

This isn't something I can fix; it's a Bukkit issue

Caused by: java.lang.IllegalStateException: BlockPhysicsEvent cannot be triggered asynchronously from another thread. 	  
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:572)

Bukkit doesn't want to let multithreading occur so I'll need to fix this seperately; I'll look into doing a patch later