diff --git a/frontend/src/views/auth/RegisterView.vue b/frontend/src/views/auth/RegisterView.vue
index ea43b8965f..a3f9c0e4a5 100644
--- a/frontend/src/views/auth/RegisterView.vue
+++ b/frontend/src/views/auth/RegisterView.vue
@@ -422,7 +422,13 @@ const confirmPassword = ref('')
 // Public settings
 const registrationEnabled = ref<boolean>(true)
 const emailVerifyEnabled = ref<boolean>(false)
-const promoCodeEnabled = ref<boolean>(true)
+// Public settings are injected into the app store before Vue mounts. Use that
+// value for the first render so a disabled promo-code field never flashes
+// while the async settings request is still in flight. If injection is
+// unavailable, fail closed until the request explicitly enables the field.
+const promoCodeEnabled = ref<boolean>(
+  appStore.cachedPublicSettings?.promo_code_enabled === true
+)
 const invitationCodeEnabled = ref<boolean>(false)
 const affiliateEnabled = ref<boolean>(false)
 const turnstileEnabled = ref<boolean>(false)
diff --git a/frontend/src/views/auth/__tests__/RegisterView.spec.ts b/frontend/src/views/auth/__tests__/RegisterView.spec.ts
index 9626a03b4a..8a9ba3a309 100644
--- a/frontend/src/views/auth/__tests__/RegisterView.spec.ts
+++ b/frontend/src/views/auth/__tests__/RegisterView.spec.ts
@@ -2,12 +2,25 @@ import { flushPromises, mount } from '@vue/test-utils'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import RegisterView from '@/views/auth/RegisterView.vue'
 
-const { getPublicSettingsMock, registerMock, showErrorMock, pushMock, verifyActionMock } = vi.hoisted(() => ({
+const {
+  getPublicSettingsMock,
+  registerMock,
+  showErrorMock,
+  pushMock,
+  verifyActionMock,
+  appStoreMock
+} = vi.hoisted(() => ({
   getPublicSettingsMock: vi.fn(),
   registerMock: vi.fn(),
   showErrorMock: vi.fn(),
   pushMock: vi.fn(),
-  verifyActionMock: vi.fn()
+  verifyActionMock: vi.fn(),
+  appStoreMock: {
+    cachedPublicSettings: null as { promo_code_enabled?: boolean } | null,
+    showError: (...args: unknown[]) => showErrorMock(...args),
+    showSuccess: vi.fn(),
+    showWarning: vi.fn()
+  }
 }))
 
 const publicSettings = {
@@ -49,11 +62,7 @@ vi.mock('vue-i18n', () => ({
 
 vi.mock('@/stores', () => ({
   useAuthStore: () => ({ register: (...args: unknown[]) => registerMock(...args) }),
-  useAppStore: () => ({
-    showError: (...args: unknown[]) => showErrorMock(...args),
-    showSuccess: vi.fn(),
-    showWarning: vi.fn()
-  })
+  useAppStore: () => appStoreMock
 }))
 
 vi.mock('@/api/auth', async () => {
@@ -93,12 +102,40 @@ describe('RegisterView', () => {
     showErrorMock.mockReset()
     pushMock.mockReset()
     verifyActionMock.mockReset()
+    appStoreMock.cachedPublicSettings = null
     sessionStorage.removeItem('register_data')
     verifyActionMock.mockResolvedValue({ token: 'ticket', randstr: 'randstr' })
     getPublicSettingsMock.mockResolvedValue(publicSettings)
     registerMock.mockResolvedValue({})
   })
 
+  it('does not flash the promo-code field before disabled settings finish loading', async () => {
+    let resolveSettings!: (settings: typeof publicSettings) => void
+    getPublicSettingsMock.mockReturnValueOnce(
+      new Promise<typeof publicSettings>((resolve) => {
+        resolveSettings = resolve
+      })
+    )
+
+    const wrapper = mountRegister()
+
+    expect(wrapper.find('#promo_code').exists()).toBe(false)
+
+    resolveSettings(publicSettings)
+    await flushPromises()
+
+    expect(wrapper.find('#promo_code').exists()).toBe(false)
+  })
+
+  it('uses injected public settings to show an enabled promo-code field on first render', () => {
+    appStoreMock.cachedPublicSettings = { promo_code_enabled: true }
+    getPublicSettingsMock.mockReturnValueOnce(new Promise(() => {}))
+
+    const wrapper = mountRegister()
+
+    expect(wrapper.find('#promo_code').exists()).toBe(true)
+  })
+
   it.each([
     ['', 'auth.confirmPasswordRequired'],
     ['different-password', 'auth.passwordsDoNotMatch']