Jamf Admin automatically zips certain packages when added to the JPS distribution point/database. When these packages are deployed via Patch Management however, the patch policies fail with the error "Installer: Error - the package path specified was invalid: <your package>.pkg.zip'.".
The installer command is expecting a .pkg but the patch policy is delivering the raw .zip file. This is not the case with regular policies. Policies seem to automatically unzip these files before delivering them to the installer command.
I propose that this functionality be extended to include Patch Management policies as well.
This comes up quite often with packages for apps that do have Jamf-supplied patch definitions such as most Adobe installers, and McAfee ENS.