I've had my Sig P238 and original spring (not flat spring) that came with it and shot various types of ammo with it (FMJ's and HP's) and have yet to have any type of malfunctions with mine. I have maybe about 1600 rounds through mine so far including HP's. I think I might be extremely lucky. Though, I will call Sig and order a new flat recoil spring for backup.
I carry MagTech +P HP's through mine. Shot about 120 through it (Various times, and not in one sitting. Because that would be bad.) and haven't a malfunction.
The only ammo that doesn't cycle through my P238 is TUL 380 FMJ Steel ammo. It doesn't cycle in my friends either.
I run mine pretty wet.
