Thank you for your post.
Our Development and Testing departments are already aware of this issue, and another person on the FileMaker forum has also encountered this issue:
In essence, List view with a large number of records may not scroll to the top or bottom manually. Only the sliding scroll bar will work.
I have attached your post to the original report. When more information becomes available, I will let you know.
Thanks for the update. I look forward to a resolution.