Scroll direction keeps changing after recent upgrade
Solution 1:
This issue is currently being tracked on the Pop!_OS github here: https://github.com/pop-os/gnome-control-center/issues/120
And on the GNOME/mutter gitlab here: https://gitlab.gnome.org/GNOME/mutter/-/issues/1505
Apologies for writing as an answer, but I can't comment currently.
The bug has been identified and a fix has been applied. The current planned release is Nov 21, but could possibly happen sooner. It appears to be backported to 3.36 and 3.38 as well.