My thanks to Joe for raising and then researching and addressing the question so fully. I had the same problem on a CZ-82, and thought it was the sear and sear spring. My gunsmith replaced them, but when the problem persisted he noticed that it was really the trigger stop disconnector. If you look at it, the right upper corner of the rectangular cut-out was clearly worn and rounded. Not being too bright, when I saw five different trigger stop disconnectors on the shop-cz-usa website, I just figured they'd messed up, or it was five different lots -- or something, so I ordered three of the same (I've got three CZ-82s, and it looked like this was a sacrificial part instead of machining the cutout into the frame somehow). So Joe's explanation was especially helpful. I'm ordering the 'set' and will work with the gunsmith figure out which one.
BTW, if anyone in the Houston-Galveston area is looking for a gunsmith that knows CZ's, I went to Lonnie and texascustomguns.net in Alvin. I'd first taken it to a name place/store on the southside of Houston, and didn't get a good vibe that they were either familiar with them, or even comfortable working on them -- or even WANTED to work on them.
