After D17672, we don't pass stopwords to the MyISAM/InnoDB fulltext engines to work around T12137.

However, this filtering applies before query tokens are stemmed, so query tokens which are not stopwords (like "having") but which stem to stopwords (in this case, "have") pass though the filter and then gum up the machinery.

Tokens should be filtered for having stopword nature after they are stemmed.