02:06 [Warning] [Stack Size Controller] Unable to get result from GitHub, code 0. If you don't have a vanilla defaults datafile, the plugin will throw errors. Reloading should resolve this unless there is something preventing downloads from external sites. 02:06 [Warning] [Stack Size Controller] If the issue persists, check the uMod forums for StackSizeController for a manual fix.

is this a bug how do i fix it?

The plugin is trying to use GitHub for something, but either the certificate it has uses too new of methods for what your server has with the game. It could switch to a Unity method to fix it potentially, else something on the server may need to be updated, or GitHub was not reachable at the time.

The server is accessing github and even pulling updates.