I had been suffering from this crash for a long time.
Also saw someone reporting it.
It is now fixed with some simple codes.

Fix this crash(occ fix):

Application has crashed: C++ exception
[string "lib/managers/occlusionmanager.lua"]:41: attempt to index local 'obj' (a number value)

SCRIPT STACK

destroy() lib/units/interactions/interactionext.lua:659
lib/units/interactions/interactionext.lua:801
unload_all_units() =[C]
core/lib/setups/coresetup.lua:646

occ fix 2 is for another similar crash. these 2 mods should not bring any issue.But if there IS issue happening to you, you can try removing occ fix 2 or put a crash log here. I don't think these 2 mod causing any issue, but I'm glad to solve your problem.

I won't help fix mods or base game issues.
For most base game issues, you can try The Fixes.