It’s probably both. The squares are actually parallelograms=out of square, disconnected circle = loose pen. If it was just out of square the circles would be ovals, and still connected. it is easy to see it wonky because of the thin and thick lines.
You are right. The fix is probably just take the 4 long bolts out of the center assembly while it is still on the rails and then put it back together. Should be good to go