diff --git a/lib/reducers/user-reducer.js b/lib/reducers/user-reducer.js
--- a/lib/reducers/user-reducer.js
+++ b/lib/reducers/user-reducer.js
@@ -258,7 +258,12 @@
   if (payload.keyserverID !== authoritativeKeyserverID()) {
     return [state, [], []];
   }
-  const newUserInfos = _keyBy(userInfo => userInfo.id)(payload.userInfos);
+  const keyserverUserInfos = _keyBy(userInfo => userInfo.id)(payload.userInfos);
+  const newUserInfos = discardKeyserverUsernames(
+    keyserverUserInfos,
+    state.userInfos,
+  );
+
   const userStoreOps: $ReadOnlyArray<UserStoreOperation> = [
     ...convertUserInfosToReplaceUserOps(newUserInfos),
     ...generateOpsForUserUpdates(payload),