When a user group is created with pages by selecting an existing site template the pages are not keeping a link to the original site template so that changes made to it are propagated.
Steps to reproduce:
1. Create a user group whose public pages are a "Community Site"
2. Open the public pages of the user group and check them
3. Make changes to the public pages of "Community Site"
4. Go back to the public pages of the user group. They have not been propagated the change.