Gosh I feel embarrased now. Thanks Sar. It looked so convincing to me that something was going seriously wrong. I’m glad it wasn’t!
Is this quite a common thing and Is there any reason why this happens mid-flight?
I've never had it happen on any of mine, but numerous videos have been posted asking about that behavior so it's probably not extremely rare either. I've no idea what causes it, or whether it is a hardware or firmware issue.