The evils of porting is like the lochness monster, a lot of people claim to have seen them but no one can prove it. As I have said before, most people who tell tall tales about porting have never touched a ported gun let alone trained with one. Way too many parrot commonly held misconceptions because some internet personality said so and they took it as gospel.
My department (and several other departments in the area) issued Glock "C" models for years and no one experienced a single issue with them. Not at night shoots, not during CQB training, not during tactical drills, not ever. Although I do agree you have to be judicious with your firearms maintenance, as you should with every gun you own.
I can definitely tell the difference in muzzle flip between my ported Shield and my non-ported Shields. But not near as much as I can tell between my Glock 23C and my Glock 23.