diff --git a/app/comp/moy_mod.py b/app/comp/moy_mod.py
index b37dac4947..673e356c0a 100644
--- a/app/comp/moy_mod.py
+++ b/app/comp/moy_mod.py
@@ -447,6 +447,12 @@ def moduleimpl_is_conforme(
         # il arrive (#bug) que le cache ne soit pas à jour...
         sco_cache.invalidate_formsemestre()
         raise ScoBugCatcher("moduleimpl_is_conforme: nb ue incoherent")
+
+    if moduleimpl.module_id not in modules_coefficients:
+        # soupçon de bug cache coef ?
+        sco_cache.invalidate_formsemestre()
+        raise ScoBugCatcher("Erreur 454 - merci de ré-essayer")
+
     module_evals_poids = evals_poids.transpose().sum(axis=1) != 0
     return all((modules_coefficients[moduleimpl.module_id] != 0).eq(module_evals_poids))
 
diff --git a/app/views/notes.py b/app/views/notes.py
index 9c69d93517..82348c3b84 100644
--- a/app/views/notes.py
+++ b/app/views/notes.py
@@ -79,8 +79,6 @@ from app.scodoc.scolog import logdb
 
 from app.scodoc.sco_exceptions import (
     AccessDenied,
-    ScoBugCatcher,
-    ScoException,
     ScoValueError,
     ScoInvalidIdType,
 )