Recently while trying to move data for one of our entities, we saw that Configuration Migration Utility was only moving 7 records out of 11.
Even in the log, we couldn’t find any error message.
<<Drive>>:\Users\<<username>>\AppData\Roaming\Microsoft\Microsoft Dynamics® CRM Configuration Migration Utility
In fact, exporting and importing the records through excel was also only adding the 7 records.
The way we fixed this issue was by specifying the primary field of the entity as the fields to compare on update.
Running the import again this time imported all the records.
Hope it helps..