I had the exact problem on mine (3055RL), cabinet above the sofa. It definitely seems to be a problem with strut - trailer is only two months old on it's first trip; I'm sill on the road so I had to fix it in the field.
I measured the distance of the mounting point of the strut with the cabinet at the opposite end of the trailer (above the table) and found that it was off by almost 1/4 of an inch. Fortunately, I carry an cordless drill and bits with me. I drilled a new hole for the strut that matched the same measurements of the cabinet that is working properly, and put some toothpicks and wood glue in the original hole so the pressure of the new hole didn't create a larger hole as I tow thus stripping out the hole. This relieved a lot of the pressure from the strut that was forcing the hinge to pull out of the door. An observation on this is when I pulled the strut off, I could see where it was causing wear marks on the wood from being attached improperly - the corrected measurement matched the bottom of the wear point!
Once that was done I removed the screws from the hinge that connects to the plastic inserts and took the door down. I then reinserted the plastic inserts into the hole and made sure they were flush with the back of the door - I did not not use wood glue or gorilla glue on the inserts - they are designed to be a pressure fit which is why the holes look so clean when they pop out. Once the glue and toothpicks set up, I remounted the door, reattached the strut to the new hole, and as of this writing it seems to be fixed. I am still cautious though opening it - I can tell you with the adjustment I made to the strut, the door now closes properly without slamming down - it was definitely in the wrong place. I did make some minor adjustments to the hinge, but these were the screws that are designed for adjusting, I did not physically have to relocate the hinge.