Minecraft 1.21.1

C&B 21.1.25

NeoForge 21.1.145

The bug is visual only and things render properly on any kind of rendering refresh, no matter what block gets changed or if you just leave and re-enter the area. It's probably safe to consider this a low priority issue.

Here's a full list of mods I had installed at the time: https://gist.github.com/SamHammie/88717078d0a734836fa8cd7f574c9376