Did the Sims react in any way, maybe by waving their hands around with a question mark over their heads? That would mean their path is blocked. I had that happen on a lot in Henford out of the blue for a room that was perfectly fine until my Sim decided it wasn't and that the path was blocked, which it wasn't. I've had that only on that one lot, so maybe that's part of your problem, too. Also, not all packs work together smoothly.
No. All sims stayed stuck even outside on an open grassy area. No waving of the arms, just standing still with arms to the sides. Stuck in the chair. When click to sit in another chair it would take a while for them to react, stand up, walk to the chair then just standing still there with their arms to their sides.
