https://youtu.be/BUdXe-5jx-8

This might be fixed by this commit: 7242a40 but I have to test it before and after that commit in this scenario.

Yeah btw, looks pretty fixed in 1.15.2:

If it's fixed in 1.15 - it means it fixed everywhere, right? Or it may still be broken on other mod-loaders?

Well 1.15+ rendering changed a bunch from earlier so that may have affected this, or maybe I have the fix cherry-picked there, I can't remember. Pretty sure it's not fixed in 1.13.2 at least, probably not in 1.14.4 yet either, since the 1.12 code still hasn't been merged yet.