Here is a report of this issue to the synaptics X.org package in Ubuntu:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1037586
And a very similar (according to the description) old report:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/830099
Here is a report of this issue to the synaptics X.org package in Ubuntu:
https:/ /bugs.launchpad .net/ubuntu/ +source/ xserver- xorg-input- synaptics/ +bug/1037586
And a very similar (according to the description) old report:
https:/ /bugs.launchpad .net/ubuntu/ +source/ xserver- xorg-input- synaptics/ +bug/830099