I’m also facing the same behavior since a few months and it’s very frustrating.
I mostly have IKEA Tradfri GU10 bulbs and some are hard to replace/reset and wasn’t something I was planning to do since it never was and issue before.
I will try to gather some logs for trouble shooting it. Which is the best approach to start with?
/edit:
Turns out that not all of my bulbs were updated so i guess that this was causing the random off/on behaviour. Will keep monitoring next weeks