The module azure_rm_virtualmachine has fields for plan information. Module azure_rm_virtualmachinescaleset needs to have them and forward them when creating a VM with an image that requires plan info to be specified. The CIS hardened images from the Azure Marketplace is a prime example.

changed = True
        except CloudError:
            self.log('Virtual machine scale set {0} does not exist'.format(self.name))
            if self.state == 'present':
                self.log("CHANGED: virtual machine scale set {0} does not exist but state is 'present'.".format(self.name))
                changed = True
        self.results['changed'] = changed
        self.results['ansible_facts']['azure_vmss'] = results
        if self.check_mode:
            return self.results
        if changed:
            if self.state == 'present':
                if not vmss:
                    
                    self.log("Create virtual machine scale set {0}".format(self.name))
                    self.results['actions'].append('Created VMSS {0}'.format(self.name))
                    if self.os_type == 'Linux':
                        if disable_ssh_password and not self.ssh_public_keys:
                            self.fail("Parameter error: ssh_public_keys required when disabling SSH password.")
                    if not self.virtual_network_name:
                        default_vnet = self.create_default_vnet()
                        virtual_network = default_vnet.id
                        self.virtual_network_name = default_vnet.name
                    if self.subnet_name:
                        subnet = self.get_subnet(self.virtual_network_name, self.subnet_name)
                    if not self.short_hostname:
                        self.short_hostname = self.name
                    if not image_reference:
                        self.fail("Parameter error: an image is required when creating a virtual machine.")
                    managed_disk = self.compute_models.VirtualMachineScaleSetManagedDiskParameters(storage_account_type=self.managed_disk_type)