Block Instance creating duplicate materials


We seem to be encountering a problem after recently running the latest update for Rhino 6 on all of our PC’s.

When importing our products which have been made into blocks, the materials seem to be duplicating themselves which never occurred before the rhino 6 update (Version 6 SR16
(6.16.19190.7001, 09/07/2019)). We have tried looking through the rhino settings and block manager to see if it was a box that’s been automatically ticked/unticked but couldn’t seem to find anything relating to the issue. We also tried starting a new file and hoping to find a prompt to pop up when inserting a new block but no luck there either.

We use the flamingo nXt 5.5 renderer to show these products, so I imagine the more duplicated textures there are in the file, then the slower the render will be as well as modelling/panning etc thus affecting our efficiency so it is important to keep this process as efficient as possible.

I’ve attached a screenshot of the problem to give an idea of what’s happening. Can someone please advise on how we can resolve this.

Thank you