When the "Powermeter Preferred" option is selected and you enter a race that enforces power from the trainer, the UI displays the power from the trainer twice: once in the primary dashboard as expected ("Power Current" data field), but also in the secondary dashboard ("Power Secondary" data field).

See the attached screenshot. This is with the default dashboard settings.

Instead, the "Power Secondary" data field should always display the power source that is not already displayed in the "Power Current" data field.