Um, I bet that the real problem is one of shooter technique.
Your thumb is contacting the pistol's slide-lock lever, and pushing upward on it as you fire, or as the gun recoils.
If your thumb, or any finger, contacts the slide lock, it will do its assigned job—even if you don't want it to.
Find a way to grip the gun without contacting the slide lock in any way. This should solve your problem.
If you are not holding this little gun with a death-grip, your hands and arms are absorbing some of the recoil force that the pistol needs, to operate correctly.
Your grip needs to be ultra-firm, and your arms need to be locked. Do that as well, and your problems will very likely disappear.
It's very easy to blame the gun, but you must also carefully assess your own technique as well.