Gary Illyes from Google was quoted as saying "We rewrite page titles in a low number of cases." Jennifer Slegg also loosely quoted him as saying "if Google is rewriting your titles, that is a sign you should work on rewriting those titles." This is from a conference named UnGagged where supposedly you are not allowed to share what you learn - but yet here we have a share.
Here is Jennifer Slegg's post on Twitter:
"We rewrite page titles in a low number of cases." Aside from adding site name to title. If Google is rewriting your titles, that is a sign you should work on rewriting those titles. @methode #GetUnGagged
— Jennifer Slegg (@jenstar) November 9, 2019
So it is kind of new to hear from Google that they only rewrite page titles, title tags, in a small number of cases. I thought Google did it more often and it was query dependent for that reason - to help the searcher click on a page title that is more relevant to the query.
The other tidbit is a bit concerning to me. Gary is saying here that if a title is rewritten that means that you might want to consider rewriting your titles yourself?
As to why this was tweeted, they got permission:
FYI, we had permission to tweet the Q&A portion of his keynote, hence the tweets from me :)
— Jennifer Slegg (@jenstar) November 13, 2019
Forum discussion at Twitter.