The timeline for one of my answers, https://math.stackexchange.com/posts/4735814/timeline, shows that my answer was accepted three times. I don't think that's possible. My answer has been unaccepted, as I can see on my reputation tab, but no unacceptance shows up on the timeline.

I'm not complaining about the unaccept – there were good and sufficient reasons for it – just asking whether it isn't usually the case that when there is an unaccept, it shows up on the timeline. For the time being, at least, I'm calling this a bug.