One of my Torklift tiedowns was stuck just like that. Seems "someone" was in a hurry to mount the TC and maybe kinda forced it into place, maybe kinda, with a 4x4. This was even after cleaning out the gravel and dirt inside very thoroughly with a hose and scraping the inside with a long screwdriver.
Then "someone" wanted to take it off after the trip and found it stuck. "Someone" had to put a 2x4 on the flange and apply vigorous hammer blows to get it to come out. It did come out. Seems there is a lot of rust and scale buildup near the end of the frame mount, probably from having moisture captured by the gravel and mud for a long time. "Someone" sprayed WD40 in there and let it soak.
Someone