Instagram could have exposed the passwords of some users due to a failure in their tools. According to an article published by The Information, the failure occurred when an Instagram user used the tool that allows downloading a copy of the data crawled by the social network. This function has mistakenly, along with the data, entered the account owner's password at the same URL, making it public.
Facebook, the company that owns Instagram, has notified users affected by the error. This personal data was also stored on Facebook.
Mark Zuckerberg's company has clarified that personal information has been deleted, as well as the tool, whose update will prevent filtering from occurring again.
Source: The Information