The map is Argelius II. I built my space station set in the black space. I looked at it some more and the weird part is that the Boffs do several different things and it's not particularly predictable what.
a: (sometimes)try to walk through, but freeze in the doorway.
b: (usually)bump into the door jamb and attempt to walk through it instead of through the door.
c: (rarely) follow the player through the door.
It's sometimes possible to manually order the Boffs to walk through, but if a: happens that won't work either. Also I tested it and it worked exactly the same in the door in the middle of a flat slab as it did on the ramps.
floor/ceiling: Building Block Platform 500x500 01
Doorway: Wall - Door 04
ramp: Building Block Ramp 40x40x80 01
picture: will be here whenever DA quits acting screwy...