Wow! That worked. Thanks a lot! It was called LibraryGlobals13.gsm.
After removing it, I tested MVO with turning on minimal space (not that I use it…), and it seems to work just the same as other AC20 objects.
Anyway, in case GS object developers see this thread: I still think the built-in basin(s) should make it back to the official set, preferably with a faucet option. 🙂