over 2 years ago - AndrewT - Direct link
I'm afraid this is a current bug in the game, which is affecting some Mac users - but not all!

It is under investigation, and will hopefully be fixed in the next patch or two.

Meantime some users report that reducing the game's graphics settings, or disabling Vsync in the game, has got past it for them. Please try that!

Sorry for that problem.  
over 2 years ago - AndrewT - Direct link
No, this is a bug in the Mac version of the game. I have hopes it will be fixed in the next patch; I don't have any sort of release date for that though, I am sorry.