After the extra duplicate points have been dissolved, everything seems to work fine. Just an extra step required.
Behavior (and workaround) are basically the same for 2.81a and 3.4.0. (Before workaround, 2.81a looks worse, probably due to older code and/or old GPU.)
[Link
https://www.instagram.com/reel/CoV_jRau0iv/?utm_source=ig_web_copy_link
to project I was working on]
