Yes it's in Blender, so it's definitely an export problem. There's not much I can do about it but delete the problematic instances and recreate a duplicate (not an instance) but it doesn't always work either.. What I need to understand is when exactly it happens so I can at least work around it..
But for this version I've managed to fix everything I found through various ways, but it's mostly a bunch of hacks and not a true solution.. But that will work for now.
I'm just trying to fix a simple issue with the nexus books and then the version will be released tonight.