This issue happens when a booking is assigned from a resource (not crew or group) to a crew or group and the value of msdyn_CascadeCrewChanges in the booking is set to false. To overcome this issue, open the booking and set the value of msdyn_CascadeCrewChanges to Yes. Then, reperform the booking assignment to a crew, which will fix the error the user sees when assigning the booking to a crew.