ShareGate is a Sharepoint migration tool that can be used to migrate the Winshuttle scripts and data files during the Foundation site upgrade
Such a method used to migrate files is causing problem when attempting to open script from the server after the upgrade
ShareGate is not supported by Winshuttle and can impact the embedded tab which causes an error
Before the upgrade :
download the script and data files, delete them from the old site, then upload them to the new site.
After the upgrade if the preventive steps have not been applied :
download the script and data template impacted, delete the impacted files from the new site and resubmit using this documented process.