How far do you guys normally take down your guns when cleaning them?
For a semiauto handgun... magazine,frame, slide, recoil spring, spring guide, slide stop, and barrel bushing if there is one.
The most critical areas to clean for reliability are the bore, breach face, and under the extractor's hook. Lube no more than the manufacturer recommends. Too much will attract gunk.
it's very probable that I may have been hitting the slide release w/ my thumb
That's my guess too. Curl your thumbs downward so they can't contact the slide stop and seeif that helps. Once you've diagosed the cause, you can experiment with fine tuning your grip, but start with one that helps you find the problem.
Good luck.
-Bulz