[Imp]

I have seen it once or twice in the distant past.
Some multi hex buildings do seem to have a problem when placing them.
To my knowledge roads are the only terrain feature that can be added to that hex once the building is placed.

however try filling a large area with trees & placing different multi hex buildings.
Some change the ground to clear & place the building as expected.
Some also clear the trees in the top left corner hex.
Some do not clear the ground the trees remain but the graphics for them vanish.
Not sure on this but a couple from memory clear terrain features from the hex row above.

Sorry if I ruined your day