So this just happened to me again, but with a twist. No glitched spiders were involved, but got 2 townies stuck on the same spot! I don't know how the initial townie was stuck, but its next to a wall corner so maybe he had set that down. Then I noticed no glass was being made so looked though my citizens and found a spot where I didn't see anybody and found the square. So I tried putting flowers over him, that didn't work. So I put a wall over him. Accidently placed down 2 walls, the other being placed first, but when the wall over the stuck townie was placed, it didnt free him but also trapped the townie with that task! Deleting the wall only freed the newly stuck townie. So I built a 2x2 section of walls around the area and that got him free, for whatever reason. Very strange...
The Evidence:


