I have not heard of any similar reports of this behavior. See if it is related to having the Enterprise PDM add-in loaded in SolidWorks at the same time you are importing the Inventor files.
I suggest you have your VAR open a service request with Enterprise technical support with details on how to reproduce this.
-Tor Iveroth, SolidWorks technical support
I am a little confused as to how unloadin the addin would help. Without it we would not be able to see the files in the vault to import.