cannot be retrieved - cannot be erased from session

So,

I got this model, that has an "Inherited Model Reference", so it should have an external inheritance feature inside that cannot be retrieved by Creo (Version 8, and 10). After you try to load this model, your session is corrupted in the following way:

1. The File > Manage Session > Object List is empty [1].
2. The Folder Browser > In Session shows the reference model [2].
3. The Folder Browser > Workspace does only contain the model I want to open [3].
4. Opening the reference model from In Session does not work (cannot be retrieved—expected, Object List).
   Opening the reference model by itself works fine. Having the reference model in session does not change the issue.
5. Erase Not Displayed looks like [4], and results in an "All the objects which were not displayed have been erased." message, but the session remains unchanged (Object List, In Session, Erase Not Displayed).

When we try to visualize this model in WVS I get the error "Failed to erase 1 files in session (-1 1)" and the publishing job fails.

Does anybody have an idea why this happens? This is not the only model with this issue.

Regards,

Hugo

[1]

[2]

[3]

[4]