Today, Valve pushed out a new client update for Steam that primarily introduced bug fixes. Although not mentioned in the official changelog, Twitter user @SteamDB discovered a new option that has been added in the client to ignore games purchased elsewhere, with Valve"s Alden Kroll confirming the change later as well.
We shipped another change based on feedback and player requests. https://t.co/eWev9oHKkL
— Alden Kroll (@aldenkroll) August 14, 2019