3.0.9

See attached screenshots; normal doors (including the quartz door) can be places on Chisel & Bits blocks. Dimensional versions, however, cannot.

2018-08-20_19 56 42
2018-08-20_19 56 51

Admittedly this is a minor issue. Not sure if it's an artifact of how rift portals are handled, or if it's due to how C&B itself handles block placement.

Can you place Vanilla Doors on non-solid C&B blocks?

Disregard that. Your screenshots tell me yes.
I assume that we're checking for isBlockSolid instead of isSideSolid or something. I'll take a look at it later this year.