Solved: Tailgate Issue
Played with the retention "locking mechanism" - turns out it was mounted on the frame a half-inch or so too high - this was the result of some body/paint work done a few years back - once I mounted this at the bottom of its adjustable mounting range (on the frame), everything worked right - the hatch pops open with either the key or the release lever - longtime mystery solved.
Played with the retention "locking mechanism" - turns out it was mounted on the frame a half-inch or so too high - this was the result of some body/paint work done a few years back - once I mounted this at the bottom of its adjustable mounting range (on the frame), everything worked right - the hatch pops open with either the key or the release lever - longtime mystery solved.