One rudder with the post displaced could have had it internal webbing still connected to the rudder post but internally bent. The rudder may have been jammed against the hull so it was pinned there by the trailing edge which was wedged up. The other rudder may have also been wedged, but the internal web was sheared away, allowing the core to rotate.

I have no explanation why they could move one rudder differently while the two were linked unless the link was broken or had been disconnected by them?