Summary
If a player changes world, for some reason their armor changes by a Netherite one and also their main weapon. When they leave and then rejoin, they spawn in the previous world, and their armor/weapon gets to normal.
Current behavior
Player Data not saving. Players can dupe.
Intended correct behavior
When they change world / leave, their data gets saved. Also, their armor is not changed.
Server log file
Proposed fixes
It is strange that armor and weapon gets replaced by netherite, maybe, because I have some Vanilla mobs changed to appear with netherite, the plugin is somehow applying their equipment to players too.
Notes: I can not update to the latest MythicMobs because of errors I have already reported in the MythicLib issue tracker.
EDIT: I found this error while stopping the server: https://pastebin.com/2MH7NjU1