Validations on page not displaying, because Cart Model is missing properties. Invalid Model causes Null reference exception

[mapadm]

CartController, Summary Post Method (Line 74:)

CartVM.ServiceList.Add(_unitOfWork.Service.Get(serviceId)); Change to:
CartVM.ServiceList.Add(_unitOfWork.Service.GetFirstOrDefault(u => u.Id == serviceId, includeProperties: "Frequency,Category"));

Similar to Summary Get Method