when adding a PR link, autolinker substitutes for the right markdown to display, but it is rendered without the last part. I've also seen this behaviour on github bot summary message
expected: text from link's markdown is displayed fully
observed: see screenshots
seen on firefox and desktop app, release and daily
it might have to do with: although i started seen this on release server yesterday
Test that full link text displays even when it exists in multiple elements as in the example provided.
Regression test more common cases of posting a link in markdown.
As a precaution, regression test plugin pop-overs.