Copied assembly does not save new reference

Hi all,

Hopefully there is anybody who can help me with this one.

I have an assembly which contains a couple of references between assemblies and parts.

Everything works well and updates nicely.

Now i have made two copy tree's from this assembly and by either of them, when I open the assembly I'll get this question as in the picture. It seems logical that SW asks to set the reference to the new assembly, but every time I restart SW and open this assembly it will ask it again, as if it was not saved with the part. If I close the assembly and reopen it within the same SW session, the question does not pop-up.

Anybody had the same issue, or know the solution for this?

equations reference