There are no "issues" in my experience - merely "upgrades" that enhance the rifle's already stellar reliability and functionality. As I have stated before, mine was one of the first two M96s imported by Wolverine Supplies. It is/was a fine piece of kit. The "upgrades" simply enhance what has always been a highly functional rifle.
FWIW, as an M96 owner for the past 5 years. If you are concerned, then contact Wolverine Supplies. They don't just warranty the purchaser - they warranty the firearms that they sell. You can be the 3rd-hand owner of a Robarm, Armalite, Accuracy International, etc, product and Wolverine will take care of you as if you'd bought the rifle new from them. And that is no crap.
Buy a gun from Wolverine's dealer line-up, and have no concerns. They are golden when it comes to customer service. Not that you will have any problems with a Robarm M-96. They are good to go. Just ask my 2 x AR's currently collecting dust in the safe.....
Mark C