I was on my first Mac ride today. I had a few apps open in the background (Lync 2013, Outlook 2015, Twitter and messages in addition to Zwift.
After the ride, the normal prompt to continue or save popped up. When I went to save, it prompted for Discard or Save+Strava. I clicked the save and it just hung. Waited a few seconds and clicked it again. SBOD appeared but quickly disappeared. At that point I decided to play a bit. All apps were still responding. I could click the discard button and the save button. They would bounce and about 2 seconds later they would bing. After 30 seconds, the screen just closed. I looked in Strava and the ride did save. The way it closed, I would have guessed it crashed.
Second issue. On the pause screen, none of my previous power numbers were represented. Not sure if this is due to this being my first ride on a Mac and those are not shared cross platform.