I'm a bit lost.
CUS errors shouldn't affect map rendering and generally shouldn't throw errors like this.
I guess you will need to do the following:
1. Go to the last working graphical preset. Reload Zero-K lobby. Make sure Calamity looks well.
2. Screenshot or right down the individual graphical setting on a) Last working graphical preset b) Preset where you have visual glitches.
3. Now go to the last working graphical preset and change setting one by one for those that are different between presets. Load Calamity and observe if changing some the individual setting break things.
Might sound like a lot of work. Yeah it's. But this way I found one particular setting due to which my FPS was dropping from 80 to 1 on older GPU.
EDIT: Actually there is one extra idea. Assuming you are are in skirmish, when in game on this map and see the bug, type into the chat:
/cheat
/luarules disable
/luaui disable
/advmapshading 0
/advmodelshading 0
See if any of last 4 have any effect.