Not sure if this will help you, but maybe it will help someone…
I have multiple access points in my home and was able to resolve this issue by “bind”-ing the bulbs to a specific access point. This feature available on my ASUS router. It was just a couple of clicks for each bulb and was easier than dealing with the bulbs in a separate network.
I noticed that the bulbs were roaming between access points. This shouldn’t be a problem, but seemed to confuse them. I’ve had no issues since I made this change (knock on wood!).