I'm not sure if there is much you can do to save the snap that's starting to separate.
I have what I assume was a field-repaired cartridge belt that had the same issue. Here are some photos:
The person who repaired this belt cut off the inner strap with the female part of the snap, sewed it onto the flap of that cartridge pouch, and then slit a hole into the flap so it could be threaded through and secured to the male part of the snap on the cartridge pouch.
What a great idea!