I just came across a non-answer in the Low Quality Posts review queue on the site where I'm a mod. I clicked "Delete", picked one of the auto-comment options, and got a little red error message (whose text was something like "a problem occurred during deletion"). So I clicked "Delete" again, and got the same error message.
Then I went to the actual page the answer was on, and it was showing up with three pending delete votes - two mine and one earlier one from a non-mod 20k user - even though three is supposed to be enough to delete an answer even with no mod involved!
Finally another non-mod 20k user voted to delete and the post disappeared. We ended up with this weirdness:
As you can see, my voting to delete twice from the review queue was registered by the system (both comments show up, and I'm listed as one of the delete voters), but my reviews don't show up in the review queue history, and for some reason it didn't count as a binding mod vote.
Maybe this is just a one-off issue, but I figured it was important enough to be worth reporting, if moderator deletions aren't working.