Ensure that load classifications and demand factors are either set up or transferred into the default electrical project in which you are going to create your panel schedule templates.
If you set up shading in a branch template for a 3-phase panel, which is a template that can be used to generate schedules for both single-phase and 3-phase devices, the phase columns do not get shaded properly for single-phase devices (whether displayed or hidden, as specified in the Circuit Table).
To fix this issue, either remove the shading or create a different template for single-phase panels, and shade the phase column(s) accordingly in the template. Then the panel schedules generate as expected when attached to a single-phase device.