The game freezes when generating a new world. The game does not crash by itself, it simply freezes; I had to close it from the task bar. The crash logs indicate a problem with UndergroundStyleGenerator.java.

I was trying out new mods for mi pack when the issue appeared, but generation worked fine before. I suspected a conflict with Spelunkery, but the issue persisted after uninstallimg it. I tried the same mod pack in 1.20.1 (excluding mods not ported yet; relevant, some affecting world generation such as Team Abnormals' Environmental, Caves and Cliffs, and Atmospheric) and world generation worked fine.

crash-2024-06-26_23.43.29-server.txt
crash-2024-06-26_23.30.45-server.txt

Disabling Quark and its dependent solves the problem.

The game crashes when loading new chunks on previously generated world too.

Deleting config files seem to solve the problem. Previously I had the azalea wood, limestone, mob variants and rope features disabled. Before deleting the config files, I again enabled limestone, but the issue persisted.

Enabling the azalea wood feature resolved the problem with new world generation and with chunk generation in old worlds.