Landing alongside minor changes like automatic timezone detection and a minimise button in the file manager, the update accidentally enabled the so-called ‘Australian scrolling’ feature by default, regardless of your own settings.
Also known as ‘natural scrolling‘, the behaviour flips the traditional two finger scrolling (i.e., scroll down to move a page up) to work more like a touch device, where dragging up moves a page up.
While Chrome OS includes an option to enable this system-wide in the Settings pane it’s not set as the default. Not wanting anyone to get too upset, a Chromium developer explained the situation over on Reddit, writing:
“Hey folks, this [change] was a mistake. What happened is we were doing some code refactoring (removing the Australian scroll handling from one place and adding to another place). Mid-move, a dev-channel release was done. Oops!
I just approved the fixes so the next build should be fine.”
Until that update get pushed out you may want to manually ‘reset’ the touchpad. This can be down through Settings > Mouse & Touchpad > Scrolling.