Starting on Gleba because I felt like it and I can't place a hatch onto a biochamber. Feels like that should be possible.

Edit: I tried it on an assembly machine and couldn't place it either. something doesn't seem right.

It definitely should be, do you have any other mods installed that might affect collisions of things? It seems to work okay for me

I think it might have been the Maraxis planet mod or one of it's requirements, because I removed it and a couple others and it works. The others just changed pipes and cosmetics.