diff --git a/src/stores/FlairStore.js b/src/stores/FlairStore.js
index 1ac518a4f6..d848ca7dda 100644
--- a/src/stores/FlairStore.js
+++ b/src/stores/FlairStore.js
@@ -129,7 +129,11 @@ class FlairStore extends EventEmitter {
         }
         const updatedUserGroups = resp.users;
         usersInFlight.forEach((userId) => {
-            this._usersPending[userId].resolve(updatedUserGroups[userId] || []);
+            if (this._usersPending[userId]) {
+                this._usersPending[userId].resolve(updatedUserGroups[userId] || []);
+            } else {
+                console.error("Promise vanished for resolving groups for " + userId);
+            }
         });
     }