When building outline may be green but can't place

When building multi-story structures and you try to place a tile, it may show green as if it can be placed but when you click to place it nothing happens. It is most easily replicated by attempting to build an overhang where one side of an overhanging wall is attached to a pillar and the other side is not supported. It has made building interesting structures impossible and I've given up.
In the attached photo the pillar is highlighted in green showing it can be placed but it cannot.
In my testing railings can be placed in some of these positions while walls cannot.

UPDATE: Attached second photo, is this the intended way to acomplish overhangs? It seems either needlessly complex or unintended, so I thought I'd include it as it may be related to the bug.