By design:

When using operation scheduling, master planning will plan capacity according to the calendar of the primary resource group. It will not take into account any calendar nor capacity of the secondary operation. It books the secondary operation at the same time than the primary. Note that this can result in scheduling the production order in a closed calendar or in a time when the secondary operation is not available (calendar closed or no capacity).

When using job scheduling master planning take into account both the capacity and calendar of the primary and secondary operations to schedule the order. Calendars for both resources of the operations must be open and with available capacity for the order to be scheduled.

The idea is to have the same possibility for operation scheduling as for job scheduling.