Documentation theme space searches 'did you mean' function rendered useless by 'ancestorid:xxxx' wording

When the 'did you mean' index is in use, searches in a space using the documentation theme are rendered useless as it constantly tries to match on 'ancestorids'. Please see attached screens shot for further clarification.

Workaround
Creating a page anywhere in the space titled 'ancestorids' will alleviate the problem.