I discovered the following regarding the dreaded VZ gremlin.
About a month or so ago took my 585 out to the range with a very good buddy of mine. The guy is a very experienced shooter (retired police officer and was the ballistics guy for the police department for over 30 years). I shoot 4 mags of 5, not a problem. His turn, 1 round ok, 2nd gremlin (as described in the forum). He cycle a new round, fired ok, next round – gremlin. This went on for several turns. He studied the way I was squeezing the trigger and compared that to the way he was doing it. He noticed that he was continuing to squeeze the trigger while the riffle was cycling the round. He then started to release the trigger sooner, and presto, no gremlin. Then this weekend went to the range with my daughters. It was their 1st time shooting the 585 (took a poor quality video, will figure out how to upload and post), they were doing the same thing and they were getting the gremlin. Got them to release the trigger sooner and presto no gremlin.
When I got back to the house, I tried to duplicate the issue with dry firing and cycling manually. I could duplicate every now and then. I have fired just under a crate of ammo and I have never had the issue.
Thought that you may find this of interest.