Steps to reproduce:
1) Create a new project or open the attached one.
2) Open Edit > Project Settings > Player Settings (or any other window that has a scrollbar).
3) Optional: Make that window short (so there would be more space to scroll).
4) Scroll the contents of the window using the scrollbar up and down really slowly.

Sometimes when scrolling, a short stutter appears - the contents of the window jump back and forth for a brief moment.

Reproduced on:
5.3.6p3, 5.3.6p2, 5.3.6p1, 5.3.6f1

Did not reproduce:
5.5.0b1, 5.4.0p4, 5.3.5f1