[1.20.1] Spigot library loader still does not work correctly

[wtlgo]

Minecraft Version : 1.20.1

Mohist Version : 1.20.1-661

Operating System : Windows 10

Logs : 1.20.1-637 / 1.20.1-661

Mod list : No mods

Plugin list : Just this one Plugin.zip

Description of issue :

As in #3052 Mohist still fails to load some plugins that rely on the Spigot library loader. I can't specify the exact plugin, since it is a private one, but I made a dummy plugin that triggers this problem, I attached it earlier.
It works correctly on 1.20.1-637, and the last versions of Spigot and Paper. Doesn't work on Mohist 1.20.1-661 anymore.