To me it looks like it slipped because of the marks from the washer. I think the Rockwood ultralites had the same issue and some one on this forum had fixed it by adding some more bolts and torqueing them to speck. Also I don't think you can just loosing them to settle back because of the torque axles would still try to push it the same way you would have to jack the trailer at the frame to get it back to the frame.
2001 Ford F-350 DRW 7.3
2011 25 RL Wildcat
former fiver 1976 Fourwinds had for 35 years