I know this is a longshot, but y'all seem like a smart group. I gifted this pistol to my father several years ago. He mentioned recently having a regular FTE issue. I shot all 6 of the 22LR varieties I had on hand (ranging from cheap white box to Eley match) through it and had similar malfunctions with all. At least 2 spent cases per mag will jam between the slide and barrel. A fresh round is always loaded. The gun feels over-sprung which given the malfunction makes sense to me (admittedly not being a gunsmith).
Googling it, I see many comments on many forums discussing the same thing, but no consistent answers about what the problem was. I broke the pistol down this weekend for a thorough cleaning, and in doing so, found a bit of corrosion in the extractor spring hole which seemed to make the extractor sticky. While I had it apart, I worked my best CZ mojo and polished literally every part which rubs against another part. The action felt much smoother afterward. Unfortunately all of my time netted no improvement. Any thoughts?
