diff --git a/services/platform/app/components/ui/editor/use-form-editor.test.tsx b/services/platform/app/components/ui/editor/use-form-editor.test.tsx
index 81540bb53..14d0926ce 100644
--- a/services/platform/app/components/ui/editor/use-form-editor.test.tsx
+++ b/services/platform/app/components/ui/editor/use-form-editor.test.tsx
@@ -119,6 +119,31 @@ describe('useFormEditor', () => {
     expect(result.current.reset).toBe(reset0);
   });
 
+  it('seeds defined defaultValues while data is still loading (controlled from first render)', () => {
+    const { result, rerender } = renderHook(
+      ({ data }: { data: Form | undefined }) =>
+        useFormEditor<Form>({
+          data,
+          defaultValues: { name: '', color: '' },
+          schema,
+          save: vi.fn().mockResolvedValue(undefined),
+        }),
+      { initialProps: { data: undefined as Form | undefined } },
+    );
+
+    // Loading, but the controlled fields already read defined values rather
+    // than undefined — no uncontrolled→controlled churn when data arrives.
+    expect(result.current.isLoading).toBe(true);
+    expect(result.current.form.getValues('name')).toBe('');
+    expect(result.current.form.getValues('color')).toBe('');
+    expect(result.current.isDirty).toBe(false);
+
+    rerender({ data: { name: 'A', color: '#FF0000' } });
+    expect(result.current.isLoading).toBe(false);
+    expect(result.current.form.getValues('name')).toBe('A');
+    expect(result.current.isDirty).toBe(false);
+  });
+
   it('reports isValid:false for schema-invalid input', async () => {
     const { result } = mount({ name: 'A', color: '#FF0000' });
     act(() => result.current.form.setValue('name', '', { shouldDirty: true }));
diff --git a/services/platform/app/components/ui/editor/use-form-editor.ts b/services/platform/app/components/ui/editor/use-form-editor.ts
index 12fbc413a..5d67585bc 100644
--- a/services/platform/app/components/ui/editor/use-form-editor.ts
+++ b/services/platform/app/components/ui/editor/use-form-editor.ts
@@ -31,6 +31,14 @@ interface UseFormEditorArgs<T extends FieldValues> {
    * want to clobber — the Convex baseline-drift fix).
    */
   data: T | undefined;
+  /**
+   * Stable, fully-defined initial values for the very first render, before the
+   * async `data` resolves. RHF reads `defaultValues` once at mount, so seeding
+   * it here keeps controlled inputs (Select/Switch) controlled from the first
+   * render instead of mounting with `undefined` and tripping React's
+   * uncontrolled→controlled warning when `data` arrives.
+   */
+  defaultValues?: DefaultValues<T>;
   /** Optional Zod schema; when present, drives validation + `isValid`. */
   schema?: AnyZodSchema;
   /** Persists the form values. Throw to keep `isDirty` true. */
@@ -60,13 +68,14 @@ interface FormEditor<T extends FieldValues> extends EditorController {
  */
 export function useFormEditor<T extends FieldValues>({
   data,
+  defaultValues,
   schema,
   save,
   mapServerError,
 }: UseFormEditorArgs<T>): FormEditor<T> {
   const form = useForm<T>({
     // oxlint-disable-next-line typescript/no-unsafe-type-assertion -- T extends FieldValues
-    defaultValues: data as DefaultValues<T> | undefined,
+    defaultValues: (data ?? defaultValues) as DefaultValues<T> | undefined,
     resolver: schema
       ? // oxlint-disable-next-line typescript/no-unsafe-type-assertion -- zodResolver returns Resolver<unknown,…>; widen
         (zodResolver(schema) as unknown as Resolver<T>)
diff --git a/services/platform/app/features/settings/enterprise-sso/components/enterprise-sso-form.tsx b/services/platform/app/features/settings/enterprise-sso/components/enterprise-sso-form.tsx
index 67155cbc0..e8e8294fa 100644
--- a/services/platform/app/features/settings/enterprise-sso/components/enterprise-sso-form.tsx
+++ b/services/platform/app/features/settings/enterprise-sso/components/enterprise-sso-form.tsx
@@ -114,6 +114,36 @@ interface SsoFormData {
   excludeGroups: string;
 }
 
+/**
+ * Fully-defined empty form state used as RHF's initial `defaultValues` while
+ * the connection config is still loading. Every field is defined (empty
+ * strings for text/Selects, booleans for Switches) so the controlled Select
+ * and Switch inputs are controlled from the first render — without this they
+ * would mount with `undefined` and log React's uncontrolled→controlled warning
+ * once the seeded `data` resolves.
+ */
+const EMPTY_FORM_DATA: SsoFormData = {
+  protocol: 'entra-id',
+  displayName: '',
+  domain: '',
+  issuer: '',
+  clientId: '',
+  clientSecret: '',
+  scopes: '',
+  pkce: true,
+  authzEndpoint: '',
+  tokenEndpoint: '',
+  userinfoEndpoint: '',
+  domainHint: '',
+  idpEntityId: '',
+  idpSsoUrl: '',
+  idpCertificate: '',
+  defaultRole: 'member',
+  autoRole: false,
+  autoTeam: false,
+  excludeGroups: '',
+};
+
 const isOidcProtocol = (p: UiProtocol): p is Exclude<UiProtocol, 'saml'> =>
   p !== 'saml';
 
@@ -404,7 +434,12 @@ export function EnterpriseSsoForm({ organizationId, config }: Props) {
     [config, organizationId, t, toast, upsertOidc, upsertSaml],
   );
 
-  const editor = useFormEditor<SsoFormData>({ data, schema, save });
+  const editor = useFormEditor<SsoFormData>({
+    data,
+    defaultValues: EMPTY_FORM_DATA,
+    schema,
+    save,
+  });
 
   useRegisterActiveEditor(editor);