Chunks stops loading when near primordial caves.
Toxic cave works just fine.
After removing the mod chunks loads once again.
Playing on newest forge 47.2.4 (tried to downgrade it to previous versions, but it doesnt work either).
Also there is no error logs in files.
Using F3 + A to reload chunks also doesnt work.

Recreated whole modpack without Rubidium, and it started working.
Weird thing was that simply disabling mod didn't work