Here we see the iOS player creates a duplicate thumbnail in the timeline, while the Mac player displays one thumbnail out of a group of seven with the wrong date.
I also see photo timeline bugs just like this with Plex for Mac 1.35.1.2632 and with the latest Windows client. But for me both players show the same incorrect behavior. So at least the bugs are consistent.
Even the Android client displays the photo timeline all wrong consistent with the bugs on Windows and Mac. So I’m guessing it’s a server issue.
My server version is also 1.24.3.5033 on Linux.