See if you can reproduce it with this simplified procedure:
Default column width = 10
CSV mode.
Fill up the view vertically (e.g. by just duplicating the first line) till the first 2+ lines are out of the view.
Then add this line at the bottom:
1234567890xxx,
Filter with “xxx”.
Adjust Separator Positions (Visible Lines Only).
** You should only see “1234567890” if the issue occurred.