As you say it is more than a year ago. I think this was a memory issue, too many things rolling at the same time, especially Studo One.
After some further investigation it seems that the error is most frequent on documents that have been created with earlier versions of Finale, but I can't say this for sure though... There seems to...
I have a MacBook Pro. I have tried 2 different mouses and the "internal" mouse with the same effect. The screen view doesnt seem to matter either...