backport of fix for issue #7630
Merge pull request #9278 from matthewrobertson/backport-hmt-counter-cache-bug

Backport of #8400 to fix for issue #7630, a bug in has_many :through counter caches.
Fixed changelog typos [ci skip]
Merge pull request #9288 from jmccartie/jm/typos

Fixed changelog typos [ci skip]