How can I fix this S&W M&P 1100078 knife that gets stuck open? - sh.itjust.works

I got this knife as a gift several years ago, I don’t really use it a whole lot but I do like to take it camping and such. However, on a camping trip a year or so ago, it got stuck open. There is some little wire loop looking thing that seems to pop out of wherever it’s supposed to be and blocks the thumb unlocker from working. I can take a tiny screwdriver or Allen wrench and poke around in there and pop the thing back into place, and then it works and closes just fine. And it’ll be fine for a few times, opens and closes correctly, but after a handful of times that piece inevitably pops back out again and locks it open. I’ve tried to use a tiny torx bit to remove the sides to see if I can figure out what’s going on, but the screws just spin. The big screw at the hinge unscrews as expected but all the little ones all act like they’re stripped. What else can I do? Is there some trick to removing the sides? Any help would be appreciated. Here’s what it looks like opened correctly with the little piece still wherever it’s supposed to be: [https://sh.itjust.works/pictrs/image/0c464150-930a-4185-afe4-b25f21e82787.jpeg] And when the piece pops out and gets stuck: [https://sh.itjust.works/pictrs/image/62b3a9a4-c259-4846-977d-32503a2b6959.jpeg] Somewhat useful red circle if you couldn’t see the problem: [https://sh.itjust.works/pictrs/image/fbd8a8dd-a704-4e12-aee2-2fc94790d44a.jpeg]