If you have the Sheld Arms Gen 1 mags with their aluminum magazine release and decided to upgrade to the Gen 2 mags you need to also upgrade to their STEEL magazine release.
My solution is to return one mag to Brownells, eat the one that I worked over the slot. I will just add a few standard 48 mags.
Hope this helps anyone looking to purchase the Gen 2 mags.
The steel mag catch is less than $30 last time I looked and there are package deals on two or three gen2 mags plus the steel mag catch where the mag catch is basically free.
Latest update. Tanner with Shield Arms is cancelling my order for the STEEL mag release and sending me one for FREE. Super nice gentleman and a great company to do business with. Hats off to them for taking care of their customer base!