Last Update: December 13th, 2016: The Windows team published an update for Windows Server 2016, which should fix the issue with DAG members crashing when restarted. The related article is KB3206632, and you can download it here. Be advised, the Windows Server 2016 update – which also fixes other issues – is nearly 1 GB!
About one month ago, Exchange Server 2016 Cumulative Update 3 was released which supported deployment on Windows Server 2016. However, recently issues are being reported on various communities as well in related blog comments, where Exchange 2016 became unstable, symptoms being randomly crashing IIS application pools (which says nothing about the root cause).
Microsoft acknowledged there is an issue with Exchange Server 2016 CU3 on Windows Server 2016:
If you attempt to run Microsoft Exchange 2016 CU3 on Windows Server 2016, you will experience errors in the IIS host process W3WP.exe. There is no workaround at this time. You should postpone deployment of Exchange 2016 CU3 on Windows Server 2016 until a supported fix is available.
So, be advised to hold off to deploying Exchange 2016 on Windows Server 2016 until further notice.
Update: The Exchange Team has also posted a notice that an update is in the works, and to delay further Exchange 2016 deployments on Windows Server 2016 until this delay has been made available. No ETA on the update yet.