I suspect I can solve your problem very easily.
I had this exact problem (EVERY time I loaded the gun), and I wound up sending it back to Rohrbaugh in August. They were mystified and could not duplicate the problem (with Karl and Eddie shooting it all sorts of ways), but modified my mag release for me. When I got the gun back, it did the same thing for me.
I had a friend try it, and it did NOT jump out for him. His son reminded me that I used to have functioning problems with a Kel-Tec P-32 that I used to own, and a light bulb went on in my head.
I have odd-shaped hands. My palms are very thin, but the heel of my hand and the base of my thumb are meaty. When I shoot (in a Weaver stance, with front-to-back pressure on the gun's gripframe), my hands tend to create a "cup" on the side of a gun's stocks.
Not a problem with most guns, but with thin-framed guns like the Rohrbaugh and the baby Kel-Tecs, it's an issue. (My friend's regular-shaped hands, and presumably those of the folks at Rohrbaugh, did not create this cupping, and the problems did not occur for them.) What I had done to get the K-T to work was I had inserted the thumb of my off-hand vertically alongside the handgun's gripframe, and I had grasped the thumb within the grip of my primary hand (thus creating a fatter profile for me to hang on to). This completely solved my problems with the P-32.
I tried the same thing with the R9s, and ALL MY PROBLEMS WERE SOLVED!
I was happy as a hog in slop! I've since fired about three hundred rounds without any problems whatsoever. (I promptly emailed Karl Rohrbaugh an explanation of what happened, so it may be he's passed my experience on to you already.)
(I would point out that a person shooting with an Isoceles stance and it's side-to-side pressure on the gripframe, is unlikely to encounter this sort of malfunction.)
What I can't tell you is how the gun's frame moving slightly within my palm (bear in mind that I was NOT limp-wristing the gun, it's just that the grip I was using was not providing adequate support to the thin, slick stocks) caused the gun to pop its mag. It apparently did, though, because the issue completely stopped when I fixed my grip on the gun.
I hope this helps. Please feel free to PM me if you have any Qs, and please let us know if this solution works for you.