I suspect like you said a bent arm. I did almost the same thing except the bottom of my awning arm stays out about 4" on the back arm. I tried everything I knew to correct this problem short of ordering new arms. I ended up drilling two small holes at the bottom of the main mountains rail (against the rig) and use a small bungie (bungie hooks in holes) to hold the arm against the trailer during travel. the slight bend does not effect the operation of the awing opening or closing.
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho