While flying the A320 FBW (developer mod) all of a sudden the cockpit view changes. All screens become blank, no knob is available (overhead and main) and there are sitting a pilot and copilot in the cockpit. I read for some people it helped to toggle between outside and inside camera. Not for me. By chance, it disappears by itself and everything is normal again. Is this a known bug?
Guess it’s a known Bug but not only in the FBW Aircraft. It’s similar in other aircraft as well.
IT happens from time to time. Either cycle through external and cockpit camera a couple of times, Escape to the pause menu and return a few times, eventually the cockpit panel kicks in again.
Thankfully the PFD and ND usually still works, so even if you need to manually handfly the aircraft, you can still do so until it restores again. I’ve done that a few times myself.
Obviously this bug appears to be slightly different to everyone. I had no panel at all. Manual flight was possible but without any flight indications it’s nearly not. Camera toggling wasn’t neither successful. So I pray for someone to find this bug and fix it 
I think the word “automatically” implies an intended or programmed change. I think the word you’re looking for would be “unexpectedly” or “randomly” to imply a bug.
Fixing this as a bug is easier said than done, given how rare and random the occurence can be. Out of all the 1,300 hours that I’ve flown in MSFS. I only had this cockpit bug 3 times across 10 months, and the total duration adds up to around 15 minutes.
So in order for someone to fix a bug, they need to be able to replicate it consistently and can be predicted. At the moment this bug is so random and so rate that you need hundreds of hours of constant flying to be able to replicate it even once. Then by the time you’re about to fix it, it disappears and you won’t experience the bug again until another hundreds of hours.
Bug fix priorities are always unplayable issues that affects everyone at the same time and consistently. And right now, this is difficult to even replicate, and much harder to fix and test.