How to reproduce:
- Set comment ordering to have the newest comments last
- Open any task with so many comments, that you need to scroll
- Scroll down to the end
- Click the smiley icon to insert an emoji
- Click the ellipsis to insert an uncommon emoji
- See the emoji list expand downwards, flowing out of the screen
- Click away
- Click the smiley icon to insert an emoji again
- Click the ellipsis to insert an uncommon emoji again
- See the emoji list jump upwards, now correctly showing completely on screen
Screenshot of how it looks after step 6 (The below edge is the end of the screen):

Happens in Chrome 99.0.4844.51, Windows 10.