In https://github.com/WebKit/WebKit/pull/7162 merge-queue is failing to process the merge request due to a merge conflict, but there is no indication of this unless you know to look at the EWS summary table. A comment or some other form of heads-up that the pull request will not be merged would be appropriate. Would also be good to apply the merge-blocked label (but that's not sufficient because it doesn't trigger a notification from GitHub).
Sorry, I'm not confident that it didn't send an email. I should double check before spamming bug reports.