Sounds like is related to the same where instanced static mesh components do not copy correctly when you try to duplicate an actor that has an instanced static mesh component, I may have to do some extensive investigation of / modifcation to Epic code and may take some, but thanks for letting me know about in friendly-fashion!
PS: summary, could take a while, please dont be waiting/dependent on a solution happening within a 2-3 weeks.
I will get to it soon as I can