Posts from good people are getting automatically removed with no trace of what is causing it

We first started noticing it this morning. It doesn't look like automod (or if it is, it isn't obvious that it is). This post is an example. This redditor has a history of posting quality images on the subreddit, but they (as well as anyone else) who posts an image is getting removed silently. We're now having to watch mod queue, unmoderated, and spam to try to catch these good posts and approve them.

Did something change in Reddit yesterday that could cause these posts to get silently removed with no trace as to why?