Metapackages that use AppleScript

Im trying to build a metapackage that runs an AppleScript App (run=only) during the post flight.
The app is called from a shell script (full paths supplied) and both the script and app are contained
in the mpkg.

The problem here that the postflight app only runs/works the very first time the Application is ran.
Sunsequent runs do nothing unless I first remove the receipt information. Though manually running
the app does work so I’m at a loss.

Any idea what might be causing this?