This may not be limited to OS X, but is applicable at least there.
I often just close the lid on my laptop with OOTP still running, then at some point after resuming might play again. However, when I do this OOTP fails to reconnect after resuming, and as far as I can tell the only way to cause it to try again is to exit the game and restart it.
I only noticed this after getting a 20-0 win in my third game of a new league that created a ton of of achievements that aren't being uploaded to
https://challenge.ootpdevelopments.com/. They do still show up locally at least.