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Mohist problems

Note: Mohist is an unofficial mod and may break plugins. I didn't code the plugin with official Mohist compatibility just because it's not something that straightforward.
Caused by: java.lang.ClassNotFoundException: net.minecraft.network.play.server.SChangeGameStatePacket$a
at java.lang.ClassLoader.findClass(Unknown Source) ~[?:1.8.0_311]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_311]
at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:106) ~[modlauncher-8.0.9.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_311]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:170) ~[forge:?]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:121) ~[forge:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_311]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_311]
at dev.lone.itemsadder.NMS.GameModeChange.impl.v1_16_R3.b(SourceFile:20) ~[?:?]
at dev.lone.itemsadder.NMS.GameModeChange.GameModeChange.J(SourceFile:39) ~[?:?]
at dev.lone.itemsadder.main.gv.U(SourceFile:138) ~[?:?]
at dev.lone.itemsadder.main.gv.f(SourceFile:184) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_311]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_311]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_311]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_311]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:315) ~[forge:?]
... 14 more

How to fix this issue

Open ProtocolLib config.yml file and set this option to false.
config.yml
background compiler: false