Above is the drawing from the TSM manual, 1980.
If the arm from the inside latch handle is bent, it could flex and not allow the inside latch to move far enough to release.
I cannot get to my doors at this time, but was wondering if the inside handle would unlock the mechanism if the lock button was depressed? If the spring is broken in the inside latch and the lock button falls to lock position, this might not let the inside handle unlock the mechanism and bend the rod.
When rebuilding mine, one door was starting to give trouble, after I lubricated the mechanism and straightened the rod, it works like new.
Just my thoughts...