Click the button that aligns objects with surfaces. The chairs are probably inset into the floor a bit, causing the issue. Or they are too close to a wall, so move them away from whatever walls they are in front of.
I just wish that we could go into first person while in them?!?! I have my throne overlooking a beautiful vista, but when I sit, it pushes me into third person! Bah!!
Weird! Sounds like you are dealing with a glitch then
Submit a ticket with CS.
Good luck. Hope it gets sorted for ya!