Mouse focus by touch screen display doesn't work correctly when there is an external non-touch screen display attached

[ovari]

* Operating System: Linux Mint 19.2 Cinnamon 64-bit
* Cinnamon Version: 4.2.3
* Linux Kernel: 4.15.0-58-generic
* Processor: Intel Pentium CPUN4200 @ 1.10GHz x 4
* Memory: 3.7 GiB
* HardDrives: 59.9 GB
* Graphics Card: Intel Corporation Celeron N3350/Pentium N4200/ Atom  E3900 Series Integrated Graphics Controller

Issue
Touch screen display works correctly if there is no external HDMI display attached.

When an external HDMI non-touch screen display is attached, pressing the touch screen does not focus the mouse to the correct position.

If the top corner of the touch screen display is pressed, when the external non-touch screen display is configured to be centred above the touch display, the top corner of the external display is selected.

Steps to reproduce

1. Turn on ASUS VivoBook Flip 11.6"
2. Add external non-touch screen display, eg
   Samsung Electric Company 22"
HDMI-2
3. Move the external monitor above the Laptop eDP-1 touch screen display as shown in the image below:
   
4. Touch the top left corner of the Laptop display with one of your fingers.
   The mouse pointer is incorrectly at the top left corner of the Samsung Electric Company 22" display

Expected behaviour
The mouse should be at the top left corner of the Laptop display, not the top left corner of the Samsung Electric Company 22" display.

Other information
Please advise any other information you require.

Thank you