diff --git a/js/src/forum/addTeamsSettings.js b/js/src/forum/addTeamsSettings.js
index d8f1f56..d237ac3 100644
--- a/js/src/forum/addTeamsSettings.js
+++ b/js/src/forum/addTeamsSettings.js
@@ -5,55 +5,60 @@ import Switch from 'flarum/common/components/Switch';
 import Component from 'flarum/common/Component';
 
 class TeamsSettingsBlock extends Component {
+  oninit(vnode) {
+    super.oninit(vnode);
+
+    // Serialisiert Saves, damit schnelle Klicks nicht zu "last write wins" führen.
+    this.saveChain = Promise.resolve();
+  }
+
+  queueSave(user, preferences) {
+    this.saveChain = this.saveChain.then(() => user.savePreferences(preferences));
+    return this.saveChain;
+  }
+
   view() {
     const user = app.session.user;
-    const prefs = user.preferences() || {};
+
+    // Sicherheitscheck: SettingsPage ist nur für eingeloggte Nutzer, aber defensiv bleibt defensiv.
+    if (!user) return null;
 
     return (
       <div className="TeamsSettings Block">
         <h3>Microsoft Teams</h3>
 
-        {this.prefSwitch(
-          user,
-          prefs,
-          'sbp-jm-msteams.enabled',
-          'Enable Microsoft Teams notifications'
-        )}
+        {this.prefSwitch(user, 'sbp-jm-msteams.enabled', 'Enable Microsoft Teams notifications')}
 
         <div className="TeamsSettings-options">
           {this.prefSwitch(
             user,
-            prefs,
             'sbp-jm-msteams.types.newPost',
             'Someone replies to a discussion I am following'
           )}
 
-          {this.prefSwitch(
-            user,
-            prefs,
-            'sbp-jm-msteams.types.postMentioned',
-            'Someone mentions me in a post'
-          )}
+          {this.prefSwitch(user, 'sbp-jm-msteams.types.postMentioned', 'Someone mentions me in a post')}
 
-          {this.prefSwitch(
-            user,
-            prefs,
-            'sbp-jm-msteams.types.userMentioned',
-            'Someone mentions me'
-          )}
+          {this.prefSwitch(user, 'sbp-jm-msteams.types.userMentioned', 'Someone mentions me')}
         </div>
       </div>
     );
   }
 
-  prefSwitch(user, prefs, key, label) {
+  prefSwitch(user, key, label) {
+    const prefs = user.preferences() || {};
+
     return (
       <Switch
         state={!!prefs[key]}
         onchange={(value) => {
-          user.savePreferences({
+          // Wichtig: Merge statt Partial-Objekt, damit andere Toggles nicht "verschwinden"
+          // (Front-end Model hält preferences als ein Attribut).
+          const merged = {
+            ...(user.preferences() || {}),
             [key]: value,
-          });
+          };
+
+          return this.queueSave(user, merged);
         }}
       >
         {label}