[GCODE generated has missing layer]

When slicing files and viewing them in layer view everything looks perfect. I then start printing the files and suddenly a layer is being skipped. 

Viewing the Gcode it first shows grey but after moving the bar on the right it shows normal layer view but a layer is missing causing failed prints.

I have tried multiple Cura versions and even uninstalling and reinstalling them.

What could be the cause?