I came across a bug in SQL Server 2016 where the Availability Group (AG) health check can get stuck in an infinite loop after removing and re-adding a database from an AG.
Unfortunately, I don’t know exactly what version this bug was introduced. I first noticed the problem on SQL Server 2016 SP2 CU7 GDR (13.0.5366.0). It may have existed before then, but I never encountered it.
Read on for a workaround. And hopefully there will be a proper fix soon. Also, it’d be interesting to see if it can be reproduced in 2017 or 2019.