diff --git a/src/Handler/Utils/Form.hs b/src/Handler/Utils/Form.hs
index c11514a07..57c590204 100644
--- a/src/Handler/Utils/Form.hs
+++ b/src/Handler/Utils/Form.hs
@@ -1136,7 +1136,7 @@ multiUserField onlySuggested suggestions = Field{..}
       |]
 
       whenIsJust suggestions $ \suggestions' -> do
-        suggestedEmails <- fmap (Set.fromList . map (over _2 E.unValue . over _1 E.unValue)) . liftHandler . runDB . E.select $ do
+        suggestedEmails <- fmap (Map.assocs . Map.fromListWith min . map (over _2 E.unValue . over _1 E.unValue)) . liftHandler . runDB . E.select $ do
           user <- suggestions'
           return $ (user E.^. UserEmail, user E.^. UserDisplayName)
         [whamlet|
@@ -1153,14 +1153,16 @@ multiUserField onlySuggested suggestions = Field{..}
       fmap Set.fromList . forM emails $ \(CI.mk -> email) -> case lookupExpr of
         Nothing -> return $ Left email
         Just lookupExpr' -> do
-            dbRes <- liftHandler . runDB . E.select $ do
+            dbRes <- fmap (setOf $ folded . _Value). liftHandler . runDB . E.select $ do
               user <- lookupExpr'
               E.where_ $ user E.^. UserEmail E.==. E.val email
               return $ user E.^. UserId
-            case dbRes of
-              [] -> return $ Left email
-              [E.Value uid] -> return $ Right uid
-              _other -> throwE $ SomeMessage MsgAmbiguousEmail
+            if | Set.null dbRes
+                 -> return $ Left email
+               | [uid] <- Set.toList dbRes
+                 -> return $ Right uid
+               | otherwise
+                 -> throwE $ SomeMessage MsgAmbiguousEmail
 
 examResultField :: forall m res.
                    ( MonadHandler m