Crash on Mac Client on Phenotype Change

I have a player who’s experiencing a crash whenever the game tries to switch to the swimming / flying phenotype. Has anyone heard of problems occurring with this, or why it might happen? It’s on build 8186 for Mac.

The problem doesn’t happen when I load the same saved game in my Windows version of the same build, so I’m tentatively assuming that it’s something client or graphics driver specific.

So I take it that no one’s seen anything like this at all?