As it fills the listbox it draws the listbox contents multiple times and you can see the scrollbar moving, almost like the programmers forgot to turn off the 'draw' flag whilst they were populating the listbox again with the data in a different order
Another thing that is annoying about 9, related in one way is that when I rename a file interactively after I hit return the old name is still being displayed. It stays this way until I do an F5 to refresh. Previously I saw the listbox being filled multiple times as it filled it with the sorted contents (this is one of the reasons that I saw it semi-frequently, enough to be annoying)
To see it fairly easily, get yourself a folder, put say 500 or so files in it, make sure you have the reset focus option unticked, change the sort order
Similarly for the rename issue, click on a file change the name to something unique then hit enter; I see the old filename again, if I attempt to change it again (file not found as you might expect). Hit F5 to refresh, watch the listbox draw and then "jump" to where your selection is again
If that isn't enough for you maybe I'll make a video of it