I may have just figured this out. I have a further child task, which is only tagged as @important. Would the sub tasks cause the other (grandparent) to show up in the search?
Translate Juan's Quotes: @due(2017-10-11) @important
- Respond to: Juan - “Re: Quote translation” @important
- message://%3C8B2610CE-03E7-41D3-A011-0E898AA9D26C@gmail.com%3E @important
Yes, all ancestors of search results (up to focused item) are included so that those results will have context. Otherwise I think it becomes really hard to understand and edit the results without making errors.