JustWondering
Jerk
That looks like an insect in the visual system to me (presuming it was some sort of display) - not moving enough (even if the system was fully locked on to it, as there often is some jitter involved), and the object rotating a little almost confirms this. My theory at least. I had a similar small bug in one of my cameras - little bleeder, and very difficult to remove!
I believe more than one pilot saw this and I think they also had a radar lock on it.