Update: As it turns out, this was not the solution. The never-ending spinner when deleting only occurs if you try to delete the post before it has been live for 60 seconds. The cron job runs once per minute. If you attempt to delete the post too early and check the Developer Tools error codes, there is a timeout/sync issue. I thought the time posted bit on the post was supposed to change by itself from "A few seconds ago" to "One minute ago", but it doesn't. I'm not sure if that can be changed.