I don't know if this will help you or not, but here's what I have:
I too remodeled because my Sims had another set of twins. Had to create an upstairs. I noticed that when I did auto floors upstairs, then went to third floor view to look at the roof, the wall I created somehow made an x near the middle of the room. The floor extended outside the wall I created, and was sticking out from under the roof. I'm wondering if that is maybe the problem? Maybe there is some blockage next to the bed on that side that is preventing her from moving?
The only thing I can think of is try going to build mode and check the floor next to the side of the bed she is on and make sure there is no half wall there - that's what happened to me, but luckily the bed was on the other side of the room.
I don't know if this helps but thought I would give a stab at it!!