This issue has been fixed in the 11/7/17 patch.
@lacedmetal I can verify what you're seeing with that particular spandrel - if you place it on the curved section first, it does indeed have the wrong orientation. However, if you hold SHIFT down while placing, it will place correctly. Or, if you place a connecting piece to it, it will also fix it. Thus, I would deem this a graphical glitch rather than a bug that adversely affects game play.
In the course of testing this, I did find something else that seemed weird to me, which was if you have walls down or in cutaway mode, the spandrels go invisible when you have a different tool selected unless you go up to the next floor. It looks quite odd, given that the columns they are connected to remain visible, and I don't recall seeing this in the past. However, I could be wrong, as I usually play and build with walls up and thus might not have noticed this before (since the spandrels remain visible in walls up mode).
Tagging @SimQARobo for awareness.
EA StaffJust want to add that in the condition where you have columns placed on the curve within two tiles of each other, the glitch cannot be manually corrected by any method I've tried. If the columns are more than two tiles apart, it's fixable. Tagging @SimQARoboagain just to update. Images:
