To clarify, two finger scroll works, but when I touch the touchpad with a third finger, sometimes it will jump to a different position on the page, and jump back once i let go of the third finger. This is very frustrating, as it's easy to accidentally touch the touchpad with a third finger when scrolling while reading.

It doesn't seem to happen all the time, but once it starts happening it keeps happening until i reboot. Can anyone help? Elsewhere I was told this is a libinput issue, but not how to fix it.