Most likely, at the end of the installation, the package return a non-standard code (other than 0 = Success no reboot required)
May be it return a code like xxx = Sucess Reboot Required (where xxx is a specific integer)
Try to find this code in Windows Update Log
May be it return a code like xxx = Sucess Reboot Required (where xxx is a specific integer)
Try to find this code in Windows Update Log