That error means one of your mods has a bug in its rendering code.
It is one of those errors where it can't tell you which mod.
Probably, the only way you will find the problem mod is to experiment with removing mods until the problem goes away.
Backup your world before removing mods.
Since the error is likely a particular block, item or mob you should think about what you might have seen for the first time when it crashed. e.g. you were in a modded biome, dimension or structure?
But here's a list of similarly reported issues on github: https://github.com/search?q="pose+stack+not+empty"&type=issues
Maybe one of them matches a mod you are using?