can you post an image of the magazines lined up next to each other showing their "catch" points?
also, can you post an image of the mag catch removed from the frame please.
i feel this is where your issue lies. E-Luder posted a "coke can" shim method in this thread somewhere (just search the thread).
i personally have used each and every mag seal i could find, and frankly i HATED every one!!! the ONLY ones that have been consistent for me are the STOCK TM/KJW ones. i am unsure why.
it sounds crazy, but they have been perfect for me, and NO OTHERS have worked more than a short time.
please keep in mind, i have built all of my non KSC/KWA glocks from a combination of parts from TM and KJW, so i am very confident in their "interchangeability" with close regard to magazines, slides, BBH, trigger mech, etc.
the fact that the gun shows issues when a mag is inserted with slide in battery, and no issue when slide is locked back, would also lead me to request pictures of the inside of the assembled slide. instinct says the nozzle is too far forward in battery, and perhaps the BBH is causing that. it is really hard to diagnose things without holding them in hand as i am sure you can imagine.
how is the BBH seated in the slide? is it stable, solid, flat?
does the BBH rattle around at ALL, or is the rear site holding it well?
also, here is what i am looking for. in the following pics you will see 2 mag catch's, one is newer, one shows more wear. these were taken out of a KJW and a TM frame (i have both sitting RIGHT HERE). this is what i am looking for from you please.
please note: the KJW mag is currently in my TM frame, and the mag baseplate from the KJ is on the TM as well. in other words, i have everything mixed up on purpose. 
