We have engineers actively working on this.
Sorry about this, I know it's a bad experience (I play on a Mac at home, too).
So many of you have provided logs, we have a lot of information to track this down. Thanks very much for your assistance.
Update [16:15 PDT]
After the deploy this morning, we're not seeing any more reports of issues, and we're unable to reproduce the issue internally.
From your logs, our engineers ended up learning that somehow the Mac players were on an old version of the game, but a new version of the client. We're looking into the deploy job because we're thinking that the Mac deploy job might have shadow failed.