CirrusSearch doesn't highlight strict phrase matches. If you search for "foo bar" or "foo bar"~3 foo and bar will be searched but not highlighted. Searching for "foo bar"~ or "foo bar"~3~ will correctly highlight foo and bar.
This tracks upstream issue: https://github.com/elasticsearch/elasticsearch/issues/3750
Version: unspecified
Severity: normal
Whiteboard: Elasticsearch_1.1
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=54020
https://bugzilla.wikimedia.org/show_bug.cgi?id=54878
https://github.com/elasticsearch/elasticsearch/issues/3757