Aim pulling up-left since 1.2

I'm playing on Steam PC with mouse and keyboard.

Since the season 2 update, my aim is constantly steering toward the up-left corner. It also does this in some menus, like the server browser for some reason. It never happened to me prior to this update.

I've tried re-installing the game, verifying its integrity, connecting a controller, un-plugging the mouse and keyboard, disabling raw input and disabling Steam controller input. Nothing fixes the issue, and it makes the game totally unplayable.

Way to update a 70€ game.