I have both guns and noticed the mag.. YOU DON'T HAVE TO DEPRESS THE MAG RELEASE.. just put the mag in and give it a push, just like most any other magazine in most any other semi. Maybe it's a little more noticeable at first, but a couple good smacks and you will realize it's fine. , but it's not hard at all once you do it a few times..
I had the same experience. I read about the issue on the forums and found it was a common issue. I ejected and reinserted with minimal assist from the eject button a few hundred times. It inserts normally now.
I did notice that after the slide is opened with empty chamber, an insertion of a new magazine will most likely cause the slide to close. I don't know if this is a feature or a defect, but it doesn't happen with my M&P 40 or 22. I did see it occur on Hickok45's video, so I'm glad it is not just mine.