I am experiencing consistently choppy scrolling in version 1.12.2 using the latest version of iOS on a 12.9 inch iPad Pro. I have an extremely large collection (over 780 GB). This was a problem sometime last year, and I reported it at that time. The problem was fixed and I was asked to let you know if the problem were ever to occur again. It most definitely has. Scrolling through my collection is currently very frustrating.