Issue Service not working correctly.

Commit messages that would create comments on issues or close open tickets are not working. Something has happened in the last 7 days that has changed how the issue service works.

I've reread the docs for it, https://confluence.atlassian.com/display/BITBUCKET/Setting+Up+the+Issues+Service to confirm that this is not an end user thing. I've also confirmed that the Issue service is still enabled for the repos (it is).