This is common to all pistols of the Tokarev design, and it has been discussed in several threads before in the Pistol forum here:
Here's one.
Another.
The solution in this one, which is an up-dated hammer (unfortunately you can't just order one off the shelf).
(I point to these just so as not to re-post a bunch of pictures from those threads.)
Start by cleaning the pistol of all the Cosmoline used for storage, or any other gunk. In particular you should remove the firing pin and spring, clean those, and scrub out the pin channel with pipe cleaners. It is the last place Cosmo will hide, and as it slows down the return of the firing pin, it increases the wipe time. Need specific instructions on dealing with the retaining pin here?
Recoil and firing pin springs are available from Wolff [gunsprings dotcom], and if your springs are weak replacing them will help a bit. However, Wolff's ‘temporary situation’ of not shipping internationally has been going on two and a half months now.
The reason it happens at all is that the firing pin is designed to directly engage the primer when the hammer pushes it, rather than to poke forward under the inertia of the strike against the force of the spring. This means when the barrel un-locks from the slide and tilts down, the pin is still in the primer, and it will wipe across the edge of the impression. This was a design choice, trading long-term stress on the pin tip for reliably deep strikes every single time.
The up-dated hammer seems to have been introduced in the 1950s, and can sometimes be found in Soviet examples of any date which have been re-furbished, as well as some other nations' models when they took on production. I have called it a notched hammer, but the difference is actually a small hump on the hammer below the part that strikes the rear of the firing pin. This hump means that when the slide recoils back, it's not pushing on the striking face of the hammer, which keeps the pin protruding into the primer. Rather the slide pushes back on the hump, which jolts the hammer back off the pin and allows it to retract a thousandth of a second earlier.
I've fired a case of surplus and counting, across a bunch of models but mostly just two of them, plus a bunch of 9mm from several Toks in 9x19, and haven't broken anything yet.