I have a Lenovo Thinkpad L450, I experienced this bug on 4.15.0 (Ubuntu 18.04) and the kernel parameter "psmouse.synaptics_intertouch=0" solution did work for me, too.
I have a Lenovo Thinkpad L450, I experienced this bug on 4.15.0 (Ubuntu 18.04) and the kernel parameter "psmouse. synaptics_ intertouch= 0" solution did work for me, too.