My drive once lost power for a minute, after which mdraid just did not wanna recognize it anymore, or rather, saw it as a part of a separate raid
So it basically showed 2 damaged raids, where one drive seemed to fit like a puzzle piece to the other raid
The solution I had to do was wiping the raid headers and just rejoin the drive to the raid which meant it had to regrow the data that was already on it
I never lost any data but still was annoying lol