When using 2 overlapping processes the 2nd process appears not to be rendered in the preview. This is either caused by the process not being generated in g-code or the process being ignored entirely.
This has happened regardless of my setup.
To recreate I simply create a process for the main model. Then I create a 2nd process for the dense support material. Since the 2nd process overlaps the first the dense support material is never rendered on the preview.
2 Process
Continuous Printing
Overlap Input Box -> Yes
Coloring Current Process
Only 1 Process Displayed except for in a few random extrusion and travel moves.
EDIT:
Adding in a factory file which displays the problem.