I don't know if this is an intended feature or a bug.  However, as long as the status is correctly marked as "uninstalled",  I personally think it is OK, especially in the case where one wants to have records of what apps have previously been installed on the device.

 

You might be able to clean this up by removing corresponding app items in specific table in the SQL database.  Please open an official support ticket with Soti support team to request for the instructions on how to do it.  Don't mess with the Database table yourself, as such action may void your entitled free technical support from Soti if your unauthorized action breaks anything in your implementation.