diff --git a/src/Handler/Corrections.hs b/src/Handler/Corrections.hs
index c3a2574fe..851c1b1c4 100644
--- a/src/Handler/Corrections.hs
+++ b/src/Handler/Corrections.hs
@@ -1085,7 +1085,7 @@ assignHandler tid ssh csh cid assignSids = do
   (btnWdgt, btnResult) <- runButtonForm FIDAssignSubmissions
 
   -- gather data
-  (assignSheetNames, nrParticipants, groupsPossible, infoMap, correctorMap, assignment, lecturerNames) <- runDB $ do
+  (assignSheetNames, nrParticipants, groupsPossible, infoMap, correctorMap, assignment) <- runDB $ do
       -- cid <- getKeyBy404 $ TermSchoolCourseShort tid ssh csh
       nrParticipants <- count [CourseParticipantCourse ==. cid]
 
@@ -1141,11 +1141,11 @@ assignHandler tid ssh csh cid assignSids = do
               in  Map.insertWith (\(usr, ma) (_, mb) -> (usr, Map.union ma mb))  uid (user, Map.singleton shn sheetcorr) acc
             )
 
-      -- lecturerNames :: Map UserId User
-      lecturerNames <- fmap entities2map $ E.select $ E.from $ \(user `E.InnerJoin` lecturer) -> do
-          E.on $ user E.^. UserId E.==. lecturer E.^. LecturerUser
-          E.where_ $ lecturer E.^. LecturerCourse E.==. E.val cid
-          return user
+      -- -- lecturerNames :: Map UserId User
+      -- lecturerNames <- fmap entities2map $ E.select $ E.from $ \(user `E.InnerJoin` lecturer) -> do
+      --     E.on $ user E.^. UserId E.==. lecturer E.^. LecturerUser
+      --     E.where_ $ lecturer E.^. LecturerCourse E.==. E.val cid
+      --     return user
 
       submissions <- E.select . E.from $ \submission -> do
           E.where_ $ submission E.^. SubmissionSheet `E.in_` E.valList sheetIds
@@ -1179,7 +1179,7 @@ assignHandler tid ssh csh cid assignSids = do
                             }
               in Map.insertWith (Map.unionWith (<>)) shnm cinf m
 
-      return (assignSheetNames, nrParticipants, groupsPossible, infoMap, correctorMap, assignment, lecturerNames)
+      return (assignSheetNames, nrParticipants, groupsPossible, infoMap, correctorMap, assignment)
 
   let -- infoMap  :: Map SheetName (Map (Maybe UserId) CorrectionInfo) -- repeated here for easier reference
       -- create aggregate maps
@@ -1218,8 +1218,8 @@ assignHandler tid ssh csh cid assignSids = do
       getCorrector (Just uid)
         | Just (User{..},loadMap) <- Map.lookup uid correctorMap
         = (nameEmailWidget userEmail userDisplayName userSurname, loadMap)
-        | Just (User{..} ) <- Map.lookup uid lecturerNames
-        = (nameEmailWidget userEmail userDisplayName userSurname, mempty)  -- lecturers may also correct in rare cases
+        -- | Just (User{..} ) <- Map.lookup uid lecturerNames
+        -- = (nameEmailWidget userEmail userDisplayName userSurname, mempty)  -- lecturers may also correct in rare cases
       getCorrector _ = ([whamlet|_{MsgNoCorrectorAssigned}|], mempty)
       -- avoid nestes hamlet $maybe with duplicated $nothing
       getCorrSheetStatus :: Maybe UserId -> SheetName -> Maybe CorrectionInfo
diff --git a/src/Handler/Utils/Corrections.hs b/src/Handler/Utils/Corrections.hs
index ca5d433d7..2fd58de80 100644
--- a/src/Handler/Utils/Corrections.hs
+++ b/src/Handler/Utils/Corrections.hs
@@ -30,6 +30,8 @@ instance Semigroup CorrectionInfo where
       mergeWith prj f = on f prj corrA corrB
 
       keepEqual (Just x) (Just y) | x==y = Just x
+      keepEqual Nothing other = other
+      keepEqual other Nothing = other
       keepEqual _ _ = Nothing
 
 instance Monoid CorrectionInfo where