Pull Request comment notifications not appearing in HipChat

Steps to reproduce issue:

1. Navigate to repository settings
2. Click on HipChat integration (under "BitBucket for HipChat" section)
3. Click "Sign in to HipChat" and sign in
4. Click "Grant Access..."
5. Select a HipChat room and click Add
6. Under "Notify room with activity in these areas:", check the Pull Request: Commented checkbox
7. Click Done
8. Make a comment on a Pull Request

Actual Results: No notification of comment appears in HipChat room

Expected Results: Notification of comment should appear in HipChat room

Note: Notifications for Creating and declining PRs are still working, if configured