I went home for lunch and really took a look at it. Here are two pictures showing it in open and closed. This is my first time really analyzing a latch like this so it may be "no duh" for some of you.
This is before I cleaned the crap out of it. You can see how the mechanism works, there is an "L" shaped lever on a pivot with a spring that tensions it into "Locked" mode. When the claws close the B portion of the lever should be pushed into the notches by a spring. When you open the release, it presses against the "A" portion of the lever and the spring on the claw pop them open. Easy peasy. As part of my standard routine I've been spraying the mechanism with lithium lube. That's all the white gunk you see.
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At first, if I pinched the claws closed the latch "B" would just sit there, no pressure into the notches. So, I tried to work the mechanism by hand and it wasn't frozen in place (ice/rust/corrosion, etc.) I could use a drift and with just my hand push on "A" to manually engage "B" while I pinched the claws closed. So it wasn't stuck. I started to clean it up to get a better look at what was going on and between that and the repeated lock/unlock cycles it seems to have started working again.
What's my takeaway? I keep my truck pretty clean, but other than spraying this lock with the lube every 5k miles or so I haven't given it any other attention. So I guess I need to keep an eye on those springs and levers to make sure they don't get gunked up with dirt. Also, no more lithium lube, I need to find something that collects less dirt and dust I think. Any suggestions on a dry lube?