diff --git a/src/Geopilot.Frontend/cypress/e2e/delivery.cy.js b/src/Geopilot.Frontend/cypress/e2e/delivery.cy.js
index 319293ec..05187454 100644
--- a/src/Geopilot.Frontend/cypress/e2e/delivery.cy.js
+++ b/src/Geopilot.Frontend/cypress/e2e/delivery.cy.js
@@ -336,6 +336,10 @@ describe("Delivery tests", () => {
     isDisabled("predecessor", false);
     cy.get('[data-cy="createDelivery-button"]').should("be.enabled");
     setSelect("predecessor", 1);
+    setSelect("mandate", 2);
+    cy.wait("@predecessors");
+    evaluateSelect("predecessor", "");
+    setSelect("predecessor", 2);
     setSelect("mandate", 0);
     isDisabled("predecessor", true);
     cy.get('[data-cy="createDelivery-button"]').should("be.disabled");
diff --git a/src/Geopilot.Frontend/src/pages/delivery/deliverySubmit.tsx b/src/Geopilot.Frontend/src/pages/delivery/deliverySubmit.tsx
index a792006c..0e3e5f30 100644
--- a/src/Geopilot.Frontend/src/pages/delivery/deliverySubmit.tsx
+++ b/src/Geopilot.Frontend/src/pages/delivery/deliverySubmit.tsx
@@ -35,24 +35,22 @@ export const DeliverySubmit = () => {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [validationResponse, user]);
 
-  useEffect(() => {
-    const mandateId = formMethods.getValues()["mandate"];
+  const submitForm = (data: FieldValues) => {
+    if (data["predecessor"] === "") {
+      data["predecessor"] = null;
+    }
+    submitDelivery(data as DeliverySubmitData);
+  };
+
+  const handleMandateChange = (mandateId: number) => {
+    formMethods.setValue("predecessor", undefined);
     if (mandateId) {
-      fetchApi<Delivery[]>("/api/v1/delivery?" + new URLSearchParams({ mandateId: mandateId })).then(
+      fetchApi<Delivery[]>("/api/v1/delivery?" + new URLSearchParams({ mandateId: mandateId.toString() })).then(
         setPreviousDeliveries,
       );
     } else {
       setPreviousDeliveries([]);
-      formMethods.setValue("predecessor", undefined);
     }
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [formMethods.getValues()["mandate"]]);
-
-  const submitForm = (data: FieldValues) => {
-    if (data["predecessor"] === "") {
-      data["predecessor"] = null;
-    }
-    submitDelivery(data as DeliverySubmitData);
   };
 
   return authEnabled && user ? (
@@ -68,6 +66,7 @@ export const DeliverySubmit = () => {
               values={mandates
                 ?.sort((a, b) => a.name.localeCompare(b.name))
                 .map(mandate => ({ key: mandate.id, name: mandate.name }))}
+              onUpdate={handleMandateChange}
             />
             <FormSelect
               fieldName="predecessor"