Building Assemblies

Can someone please tell me what's causing this? If I make a left hand turn it gets all wonky, but it works just fine if I make a right hand turn. I tried using unique instances assigned specifically to the left and right junctions, but that broke everything, so I assume junctions are meant for actual angles, not 90 degree corners? 

I've tried adjusting the setback; I can fix it in one spot, but then it'll just break in another spot. Advice would be greatly appreciated!