Issue seen with multiple external monitors via docking stations.
When session is spanned across all the screens, the resolutions on either side are not in sync and there is a disjointed black section in the middle. 
Also, the mouse control seems slightly off.
As a workaround use the desktop is windowed mode. 

On the client machine -
If we have different scaling on two displays this issue is usually observed.
For example, Scaling set for laptop screen: (Monitor 1) - 125%
Scaling set for external monitor: (Monitor 2) - 100%

Solution: - We need to set these scaling to the same value for all the displays. 
Settings> System> Display > Scale and Layout > select suitable scaling percentage, 
Select each display under this setting and make sure to set same Scale percentage. 

Problem Cause

Difference in the DPI (Scaling %) between primary and secondary monitor.