1. From the main page of a PHPBB installation, click any of
View unanswered posts • View unread posts • View new posts • View active topics
2. Notice it now says "Return to advanced search"

But that is NOT where we came from! Clicking there will only take us to a third place, not the simple BACK.

Either say the correct place, or don't say "return", or don't say anything at all.