The mag wobble on the early 2019 Z5rs batch that was imported by zenith has been discussed few times already. The magwell on them is not in specs, also the bolt it's not supposed to come in contact with the magazine when you move it back and forth. Here is one of the threads https://www.hkpro.com/forum/hk-clone...bble-play.html
Here is video of the play of my 2019 z5rs https://www.youtube.com/watch?v=aDB-h-MhdGU that was also having problem with bolt getting hung on the magazine , when the magazine was pushed forward .
This is video comparing my 2016 z5rs wobble https://www.youtube.com/watch?v=51N0WrgGC6c .
You will have to send it to zenith so they can fix the magwell .