Steps to reproduce:
(1) create site from Site Template (I've used default Community template);
(2) go to first page in site (Home), modify it (move portlet);
(3) after page refresh, you can see that no more changes are propagated, because page was changed;
(4) repeat #2 and #3 on third page in the site (Wiki), you will see the same message in the Dockbar as in #3;
(5) go to another page in site (Calendar), you can see the same content as in template;
(6) now alter the second page (Calendar) the in Site Template, by moving one portlet to another page
(7) go to second page (Calendar) in the site
First you get an error (reported as
LPS-32506), but after going to the same page for the second time (or after simple refresh in browser), you can see the second (Calendar) page now looks like in the template (correct I assume). But when going to the first page in site (Home), it now also looks as the one in template – it was reset and your changes were thrown away (wrong). I never agreed to throw away my changes and still layouts were reset. The same happened with third page in site (Wiki) – also was reset to the template version of the page.
(1) No template-linked page should get reset automatically (without user's confirmation), when any of the template-linked pages in site were modified.
(2) On second, not modified page (Calendar) in the site, you should also get the Dockbar warning, even when the page itself was not changed compared to the site template's page.