no problem on my PC ... it's probably a flaw in your workflow ... this means you do not understand how Creo works.
I am sorry I can't open you model in Commercial version, because it is created in Educational version.
indeed I'm using the academic version. It is true my understanding of Creo may not yet be as profound as yours but I'm working on it (which is the reason I asked the question in the first place).
My previous post was not entirely correct (the described workflow indeed works fine) but I think I got it now:
The problem occurred because the assembly I'm working on had been saved as a backup before I took over, which is the reason Creo saved the standard parts used at the time in the working directory and cut the links to the library. I first created the new instance in the family table of the library part, then opened my assembly (generic library part still in memory) and added the newly created instance to the library. Upon saving, Creo does not save the generic part that is now in memory but sticks to the one already present in the working directory (I tried the previously described workflow with a backuped mock assembly and could now reproduce the error).
Use Backup command to create a backup copy of your assembly, only (to save current status of development).
After finishing backup, erase complete assembly from session and open it again.
If you do not erase complete assembly from session then your next steps will be applied on backed up files.
thank you for pointing this out. As I said before, keep up the good work :).