Mine has been doing the same. I suspect its the obstacle avoidance detecting things that are not there, then realising it’s not there, then seeing it again … and so on.
As it happens so intermittently, its hard to prove, but I have tried multiple runs back and forth, and it never happens when OA is turned off, but does (occasionally) happen when OA is turned on.
I have looked at AirData and there is nothing showing there.
I discussed this previously … Has anyone else experienced a strange ‘bucking bronco’ behaviour of the Mini 4 Pro?