We installed new package and tested after clearing browser cache, We are not able to reproduce the issue.
Can you please reinstall & check once.
If its still reproducible, Can you please check the console if there is any error
If you can provide CRM & SSH access we would check and resolve the issue for you. You can share the details in crmsupport@brainvire.com
If you are talking about Email Templates module data, even if you uninstall those fields wont get deleted in the backend. In database both the fields content Sid & Content Variables data will be retained.
But to be double sure before uninstalling you can export the database table email_template and can take the backup of it.
You can uninstall the existing package and install again after taking the backup.