You are looking at the wrong end.
Look at the 'bottom' where the awning attaches. It is screwed into the side of the MH.
Sadly most of the older RV's it is screwed into the narrow width of the floor board of your MH. Which is particle board.
The screws become loose not real visible but just enough to when you put the arms up one will not catch because the bottom has dropped ever so slightly from the loose bolts. Pick the arm up and shoove it up and it will catch.
I am having to have mine rebolted on with a metal plate from inside the MH. Due to being caught in tornado that ripped off the awning and repair guy didn't check the bottom bolts and they had been pulled loose.
I struggled with that arm not catching for months before a mobile repair guys pointed out why.
We must be willing to get rid of the life we've planned,
so as to have the life that is waiting for us.