change difficuty server

[joaoespanhol]

Minecraft Version : 1.16.5

Spigot version: last
Mohist Version : 992

Logs : No crashes, no console errors

Mod list : No Mods

Plugin list : WorldMania

Description of issue : Firstly, I know this isn't a problem with WorldMania because this problem also occured when I had Multiverse instead of Worldmania. When in the "Default" world (the main world of the server, the one that can be accessed without any sort of multi-world plugin), difficulty can be changed as intended by using the /difficulty command. When attempting to change the difficulty in additional worlds, such as those made with a multi-world plugin, the difficulty will not change.

1: make a new world
2: teleport to that world, the difficulty is set to easy by default
3: do /difficulty normal (issue also occurs with peaceful or hard)
4: chat says the difficulty did not change, as it was already set to normal
5: check Options within the esc menu, difficulty still says Easy. This is confirmed as cave spiders do not deal poison damage, and raids only have 3 waves

So the game is acting like the difficulty should still be what I say it is, but its locked on easy. Again, this occurs within all worlds except that default world. I repeated the above steps using WorldMania and Paper, and the difficulty changes as intended in all worlds.

MohistMC/Mohist#1259

Observation: I tested Spigot, still the same problem.