Thank you!! Did you change the graphic settings by any chance?
Ok I think its either that unity cant handle a lot of lightsources at once on the mac build, or the mac build gets somehow build with different quality settings than the win version or the lightsources are too performance heavy. I dont really know what of those things it is but a friend of mine has access to a mac so I can test the version better but that might take a while. Hope that is alright. Im sorry for the long wait for a unfinished version of my game, I hope I get to fix the issue soon!