The issue was the serializer’s return type claimed it returned the original generic T, but the implementation intentionally removes reviewToken and rewrites customer.licenseImageUrl. I updated the return type to model the actual serialized dashboard payload: Omit<T, 'reviewToken' | 'customer'> plus the normalized customer and computed fields.

apps/api/src/modules/reservations/reservation.presenter.ts

@@ -124,6 +124,25 @@ export function buildBookingRequestProgress(reservation: {
   }
 }
 
+type DashboardReservationCustomer = {
+  id: string
+  driverLicense?: string | null
+  dateOfBirth?: Date | null
+  address?: unknown
+  licenseImageUrl?: string | null
+  licenseValidationStatus?: string | null
+}
+
+type SerializedDashboardReservation<T> = Omit<T, 'reviewToken' | 'customer'> & {
+  customer?: DashboardReservationCustomer | null
+  paymentMode: string | null
+  spareWheel: boolean
+  radioCd: boolean
+  contractFields: Record<string, string>
+  workflow: ReturnType<typeof buildReservationWorkflow>
+  bookingRequest: ReturnType<typeof buildBookingRequestProgress>
+}
+
 export function serializeReservationForDashboard<T extends {
   extras: unknown
   status: string
@@ -131,22 +150,8 @@ export function serializeReservationForDashboard<T extends {
   contractNumber: string | null
   invoiceNumber: string | null
   paymentStatus?: string | null
-  customer?: {
+  customer?: DashboardReservationCustomer | null
-    id: string
+}>(reservation: T): SerializedDashboardReservation<T> {
-    driverLicense?: string | null
-    dateOfBirth?: Date | null
-    address?: unknown
-    licenseImageUrl?: string | null
-    licenseValidationStatus?: string | null
-  } | null
-}>(reservation: T): T & {
-  paymentMode: string | null
-  spareWheel: boolean
-  radioCd: boolean
-  contractFields: Record<string, string>
-  workflow: ReturnType<typeof buildReservationWorkflow>
-  bookingRequest: ReturnType<typeof buildBookingRequestProgress>
-} {
   const extras = parseReservationExtras(reservation.extras)
   const contractFields = serializeContractFields(extras.contractFields)
   const customer =
@@ -160,10 +165,14 @@ export function serializeReservationForDashboard<T extends {
       : reservation.customer
 
   // S11: never expose reviewToken on API responses (capability URL secret)
-  const { reviewToken: _reviewToken, ...safeReservation } = reservation as T & { reviewToken?: unknown }
+  const {
+    reviewToken: _reviewToken,
+    customer: _originalCustomer,
+    ...safeReservation
+  } = reservation as T & { reviewToken?: unknown }
 
   return {
-    ...safeReservation,
+    ...(safeReservation as Omit<T, 'reviewToken' | 'customer'>),
     ...(customer !== undefined ? { customer } : {}),
     paymentMode: typeof extras.paymentMode === 'string' ? extras.paymentMode : null,
     spareWheel: typeof extras.spareWheel === 'boolean' ? extras.spareWheel : false,