2 things -
#1 - Unable to unhook on an angle.... In all the years I had my Superglide, NOT ONCE did I have an issue because of not being straight.... ..A little fore sight and planning..
#2 - unable to unlatch - .. I ONLY had this issue a few times, to correct it I would: place the trailer brakes on and hit reverse... once It am tight against the front of the hitch head, place the parking brake on an d place it into park... Get out and the handle would release 100% of the time...
Like stated before, sometimes they like to have the pressure removed from the rear of the jaws..