Possible bug on Desktop Scroll Bar

Description of the issue: White coloured scroll bar vanishes or is not available and empty space is seen. Empty space is background tab, usually the last tab opened or the next tab in line of tab sections.

How can this issue be reproduced?

  1. By normal everyday browsing it may be seen

Expected result: Scroll Bar vanishes or not available

Brave Version( check About Brave): [
Version 1.31.88 Chromium: 95.0.4638.69]

Additional Information: I have uploaded screenshots which I took. Second photo is the one it should be, but first and third photo show it is bugged. If it is a bug then, do create a topic/issue on github as I am not on github and not a coder/programmer.