I don't see how that could happen, and never seen it before.
I have seen the knob on the end pop off and park wouldn't lock.
If it were me I'd disconnect the linkage from the trans and see if it was the trans or the linkage, and if it was the trans I'd pull the pan and push the tang back from the manual valve and see if it moved like it should.
Then if the valve moved I would start looking at the neutral safety/backup light switch.
If it wasn't jamming it then it'd VB removal time to see what got in where, because it seems weird that the valve would just jamb up for no apparent reason.