**Steps to replicate the issue** (include links if applicable):
* Using account 1, create an article
* Using account 1, watchlist the article
* Using account 2, make an edit to the aforementioned article
* Using account 1, without re-visiting the aforementioned article, visit your watchlist. Make sure individual revisions are turned on, blue "unread" dots are turned on, folding is turned on. Should look like this:
{F36973122}
* Using account 1, on your watchlist, click "prev" for the oldest revision of that page
**What happens?**:
* All diffs for the watched article are marked as read. Note the open circles in the screenshot below.
{F36973112}
**What should have happened instead?**:
* Only diffs occurring on or before the clicked edit should be read. Note the blue solid circles in the screenshot below indicating that those diffs have not been read.
{F36973114}
**Software version** (skip for WMF-hosted wikis like Wikipedia):
**Other information** (browser name/version, screenshots, etc.):
* The URL of the diff I clicked in this example was http://localhost/Code/MediaWiki/core/index.php?title=Test&curid=2&diff=4&oldid=3
* Seems intermittent to me. I don't usually have this problem, but I've spotted it enough times for it to stand out as a possible bug to me.
* I tested visiting just the history page, in case visiting the history page was marking all revisions as viewed. Result: that was not the problem. Visiting just the history page preserves "updated since your last visit" and green circle markers, even after refreshing twice.
{F37130037}