diff --git a/frontend/src/views/admin/SubscriptionsView.vue b/frontend/src/views/admin/SubscriptionsView.vue
index d31578c9be..840ee477c8 100644
--- a/frontend/src/views/admin/SubscriptionsView.vue
+++ b/frontend/src/views/admin/SubscriptionsView.vue
@@ -1126,6 +1126,11 @@ const clearFilterUser = () => {
 
 // User search with debounce
 const debounceSearchUsers = () => {
+  // Invalidate the assignment target before the debounced search runs.
+  if (selectedUser.value && userSearchKeyword.value.trim() !== selectedUser.value.email) {
+    selectedUser.value = null
+    assignForm.user_id = null
+  }
   if (userSearchTimeout) {
     clearTimeout(userSearchTimeout)
   }
@@ -1135,12 +1140,6 @@ const debounceSearchUsers = () => {
 const searchUsers = async () => {
   const keyword = userSearchKeyword.value.trim()
 
-  // Clear selection if user modified the search keyword
-  if (selectedUser.value && keyword !== selectedUser.value.email) {
-    selectedUser.value = null
-    assignForm.user_id = null
-  }
-
   if (!keyword) {
     userSearchResults.value = []
     return
diff --git a/frontend/src/views/admin/__tests__/SubscriptionsView.userUsageLink.spec.ts b/frontend/src/views/admin/__tests__/SubscriptionsView.userUsageLink.spec.ts
index d9b4ae68fe..7ae5e82da5 100644
--- a/frontend/src/views/admin/__tests__/SubscriptionsView.userUsageLink.spec.ts
+++ b/frontend/src/views/admin/__tests__/SubscriptionsView.userUsageLink.spec.ts
@@ -4,8 +4,10 @@ import { defineComponent } from 'vue'
 
 import SubscriptionsView from '../SubscriptionsView.vue'
 
-const { listSubscriptions, getAllGroups, listUsers, searchUsageUsers } = vi.hoisted(() => ({
+const { listSubscriptions, assignSubscription, getAllGroups, listUsers, searchUsageUsers, showError } = vi.hoisted(() => ({
   listSubscriptions: vi.fn(),
+  assignSubscription: vi.fn(),
+  showError: vi.fn(),
   getAllGroups: vi.fn(),
   listUsers: vi.fn(),
   searchUsageUsers: vi.fn()
@@ -13,7 +15,7 @@ const { listSubscriptions, getAllGroups, listUsers, searchUsageUsers } = vi.hois
 
 vi.mock('@/api/admin', () => ({
   adminAPI: {
-    subscriptions: { list: listSubscriptions },
+    subscriptions: { list: listSubscriptions, assign: assignSubscription },
     groups: { getAll: getAllGroups },
     users: { list: listUsers },
     usage: { searchUsers: searchUsageUsers }
@@ -22,7 +24,7 @@ vi.mock('@/api/admin', () => ({
 
 vi.mock('@/stores/app', () => ({
   useAppStore: () => ({
-    showError: vi.fn(),
+    showError,
     showSuccess: vi.fn()
   })
 }))
@@ -80,6 +82,7 @@ describe('admin subscription users', () => {
       total: 1,
       pages: 1
     })
+    assignSubscription.mockResolvedValue({})
     getAllGroups.mockResolvedValue([])
     listUsers.mockResolvedValue({
       items: [{ id: 42, email: 'reader@example.com' }],
@@ -143,6 +146,50 @@ describe('admin subscription users', () => {
     }
   })
 
+  it.each(['another', ''])('clears the assignment user immediately when input changes to %j', async (keyword) => {
+    vi.useFakeTimers({ toFake: ['setTimeout', 'clearTimeout'] })
+    const wrapper = mountView()
+    try {
+      await flushPromises()
+      await wrapper.findAll('button')
+        .find((button) => button.text() === 'admin.subscriptions.assignSubscription')!
+        .trigger('click')
+      const form = wrapper.get('#assign-subscription-form')
+      form.getComponent({ name: 'Select' }).vm.$emit('update:modelValue', 3)
+      const search = wrapper.get('[data-assign-user-search] input')
+      await search.trigger('focus')
+      await search.setValue('reader')
+      await vi.advanceTimersByTimeAsync(300)
+      await flushPromises()
+      await wrapper.get('[data-assign-user-search] button').trigger('click')
+
+      await search.setValue(keyword)
+      await form.trigger('submit')
+      await flushPromises()
+
+      expect(assignSubscription).not.toHaveBeenCalled()
+      expect(showError).toHaveBeenCalledWith('admin.subscriptions.pleaseSelectUser')
+      expect(listUsers).toHaveBeenCalledTimes(1)
+
+      listUsers.mockResolvedValue({ items: [{ id: 84, email: 'another@example.com' }] })
+      await search.trigger('focus')
+      await search.setValue('another')
+      await vi.advanceTimersByTimeAsync(300)
+      await flushPromises()
+      await wrapper.get('[data-assign-user-search] button').trigger('click')
+      await form.trigger('submit')
+      await flushPromises()
+
+      expect(assignSubscription).toHaveBeenCalledTimes(1)
+      expect(assignSubscription).toHaveBeenCalledWith({
+        user_id: 84, group_id: 3, validity_days: 30
+      })
+    } finally {
+      wrapper.unmount()
+      vi.useRealTimers()
+    }
+  })
+
   it('keeps deleted users available when filtering subscription history', async () => {
     vi.useFakeTimers({ toFake: ['setTimeout', 'clearTimeout'] })
     const wrapper = mountView()