The Search Engine service finds nothing when the section of the site to look into is input in its settings. When this setting is blank (all sections unchecked, meaning the search will be performed globally), the Search Engine service works just fine.

How to reproduce:

• Empty the Section setting in the Search Engine service configuration (uncheck everything) and search for a word that you know is there (such as "ipsum" or any other part of the placeholder text). The service will find a list of pages containing the word, like it is supposed to.
• Now in the settings of the Search Engine, enable the Section setting by selecting one of the pages the service had just found, and repeat the search. There will be no result.