Don't think I can edit the post, but forgot to mention an importannt bit of information - this is using core 3.1.4 and gamekit 3.0.0.

I see. Thanks for the response. We need to know which versions of MacOS we can support. Right now the lowest version Unity supports is 10.13, which is what we have targeted so far. But if the plugins are not expected to work for that version, we can drop support for those versions since they are integral to the online experience of our game. The reason I am asking is because since there is no explicitly stated lowest supported version, I was not sure if the fact that it does not work on 10.13 is a bug, or intentionally not supported. Having some sort of "minimum OS version requirement to run" on the GitHub page would be helpful for this purpose.