Good news or bad one first?
Full mag does not change anything until a round is loaded to barrel, so it still has OOB
And maybe,
just maybe, it's still not an actual "problem" as long as it's only something that happens when you intentionally try to make it happen.
All the out-of-battery checks I've ever been taught in armorer classes involve doing it with an empty chamber, looking to check for intended disconnect function, not using dummy rounds to see if extractor friction can cause it when SLOWLY (improperly) checking for FEEDING & LOCKING. Such feeding checks with dummy rounds are done at the "normal" speed, meaning letting the slide run forward so proper "timing" occurs.
It worries me about having a slide/barrel pushed out-of-battery by contact about as much as it worries me to have a cylinder stopped in its rotation during a DA/DAO trigger press by someone grabbing it.
I make sure it doesn't happen during proper holstering, and then I don't worry about it happening at some other time.
FWIW, I can still MAKE this sort of thing happen with some different pistols, if I try and MAKE it happen, and all of the guns are in normal tolerance and good condition. I don't worry about them being pushed out-of-battery when carrying them, either.
On the plus side of things, if the slide wasn't locking back on an empty magazine, and it is now, that's good. It also sounds like they tried to make a customer happy by essentially rebuilding the gun with the latest revisions of almost all of the parts & assemblies (except for the serial numbered frame

).
Lucky you.