Good to hear that they are replacing the parts, but unless yours was a fluke, until they start making the base plate out of stronger material, it may just keep happening.I received an email from MG today. My case was the first example of this type of malfunction and they are assuming that it was a defective part.
Replacement locking plate and baseplate are en route as a warranty replacement.
I just got my new spring sets yesterday and I'm not impressed by the sharp edges. I ended up with a few minor cuts while assembling the first mag. I assembled 1 with the factory Shield base plate and 1 with the new +2 base plate, just to compare the 2 setups with their original spring set.