safety engaging while firing

[DonVoigt]

Stout ammo does not help.
This is a frequent problem with the Stoeger.
The "nub" on the safety lever is probably worn, and the arm itself lost some tension.

I have replaced completely worn "nubs", and also carefully bent the arm to increase tension.
If it is a "shooter" you may choose to buy another safety lever with a better nub and more tension.

But that would be hit or miss when ordering.

Or you could send it to lugerdoc.