Whenever I try to invoke an operator command, be it a vanilla command such as /kick or a modded command such as /yigd (from You're In Grave Danger) I get a "Cannot invoke" error and the command doesn't execute.

I haven't been able to test different mod configurations as the server is live and in-use.

latest.log

Seems like a race between onCommandTree and onGameJoin.

Do you have the same mods on the server, I assume its also a fabric server.

Would be nice if we can reproduce this with a minimal set of mods.

Do you have the same mods on the server, I assume its also a fabric server.

Would be nice if we can reproduce this with a minimal set of mods.

This is what I checked first. Copied the mods list directly from the server into my client and it had no effect. I'll try to reproduce with minimal mods this evening.

Okay, I've just done a load of testing. Here's what I've found.
The issue occurs:

• on singleplayer worlds as well as multiplayer servers
• only on the FIRST world load of any Minecraft session
• 100% of the time on dedicated servers, as every server load is the first world load
• with only Accurate Maps, Fabric Language Kotlin, and The Twilight Forest installed

The issue does not occur:

• when Accurate Maps is removed, but Fabric Language Kotlin and Twilight Forest are still installed
• when Twilight Forest is removed

So it seems to be a conflict between Accurate Maps and The Twilight Forest. I'm still not 100% sure whether you can do much about this, I'll leave that to you to tell me, but I will report this to both the developers of Accurate Maps and Twilight Forest.

This is indeed probably not a Fabric bug.