Cannot un-bury the joint

[sutcac]

Try changing your railing wall type from the Default to a 4" Siding or something where the outer layers match that of the wall they abut. You may like how this works out better.

As I suspected, the deck is 17-1/2" lower than the adjacent floor, likely explaining to some extent how it is being modeled and viewed in 3D and how the half post is working there. Don't have a auto-generate solution for you there, but you can modify the framing manually so that the section/detail etc. will show properly.

For your stairs, draw them in place, don't draw them in another room and then try and move them into place.