Unfulfilled Purpose
Scientists speculate too much. Although it may appear to be a separate entity, the 'third belt' isn't separate at all. What they are observing is the reproductive cycle of the smaller belt. The changed appearance and erratic behavior might lead them to believe the 'third belt' is a completely different object but that is not the case. The observed behaviors are normal, and although inconvenient to the larger belt, these symptoms, as noted, will pass.
Instead of probing the third belt during this period they should be increasing their focus on the larger belt and attempting to mollify the smaller belt. Perhaps pointing out how nice it looks and how interesting it is. Making a big scene out of the 'third belt' only introduces more chaos to an already unstable situation. The worst possible thing they can do would be to give the 'third belt' some sort of name. That will guarantee they will never be able to study either belt in a non-agitated state ever again.