Yes, this ^.
I suspect what JSEYMOUR describes is exactly what happens. Power goes out and comes back on, B-hyve tries to reconnect to wi-fi (or internet) that hasn’t yet come back (router still re-booting), B-hyve gives up and calls itself “offline”, B-hyve doesn’t try to reconnect beyond that point, email message received that controller is offline.
I’ve pulled the plug on the B-hyve and restarted it many times while the router remains powered and the controller reconnects without issue.
For me, it only seems to happen when they both lose power at the same time.