First impressions of stairs

So far in my 30 minutes of trying to fix up my existing stairs in my house i'm finding a few issues I don't understand yet. When I try to L-shape the stairs I get a "wall" or "fence" issue. I tried deleting the stairs I had and starting from scratch which seemed to fix the fence problem I had (which I assume was caused by the railings) but there's still a wall issue. I can't see any walls that would affect the stairs. So.... not sure yet.

Also, since the update, I lost the ability to create foundations. The foundation slider is gone. Is anyone else having this issue, or is it maybe just me?