Unfortunately it seems that for some Twitter users, a recently discovered bug has accidentally revealed the location of these users. According to Twitter, it appears that this bug has affected those who might have location sharing recently enabled, and where following a specific set of actions, their tweets gave away a city-level location, which we can imagine is probably more than what some had expected.
We've removed the locations from potentially affected Tweets & are directly emailing those who may have been impacted, if an email address has been provided to us. We take these types of issues seriously. We’re sorry this occurred & will continue our work to make Twitter better.
— Support (@Support) November 24, 2017
While that is rather scary to know that you’re being exposed like that, it seems that it might not necessarily be that big of a deal. Subsequent tweets by users have revealed that for some of them, the city-level location that was shared was completely wrong. Some are claiming that their location is based on what they might have recently searched for, while for others it seems to be completely random.
However Twitter has since claimed to have removed the locations from these tweets and have reached out to those affected via email.