I'm having the exact same issues, it's hard to load the 13th round in the magazine without a Uplula. Then with the full magazine it's hard as hell to rack slide but with only12 round in it it's a lot easier.I'm late getting in the game (New Years Eve 2021). I just purchased the 3.1" Sheild Plus (Optic Ready). I am also having problems loading the magazines. Like Ralph, I can manage to load the 10-round mag with the Magula UpLula loader. However, loading the 13-round mag is next to impossible even using the Uplula. I have to push down on the top of the loader with the palm of my hand with everything I have (I'm 200lbs.) to get the 13th round in the mag. The little "beak" looks like it was going to snap! I can't believe that this is normal for any new magazine.
Then trying to load the full mag in the gun is crazy hard. It can't be good for the gun to have the mag slammed into it that hard. Then racking the slide is another huge undertaking. I've shot 120 rounds through the gun and it is still the same.
To me, this just is not acceptable on a $560.00 gun!!