diff --git a/app/models/instructeur.rb b/app/models/instructeur.rb
index c03c87a16..86f7aa4e4 100644
--- a/app/models/instructeur.rb
+++ b/app/models/instructeur.rb
@@ -108,24 +108,17 @@ class Instructeur < ApplicationRecord
   end
 
   def notifications_for_dossier(dossier)
-    follow = Follow
-      .includes(dossier: [:champs_public, :champs_private, :avis, :commentaires])
-      .find_by(instructeur: self, dossier: dossier)
+    follow = Follow.find_by(instructeur: self, dossier:)
 
     if follow.present?
-      demande = follow.dossier.champs_public.updated_since?(follow.demande_seen_at).any? ||
-        follow.dossier.groupe_instructeur_updated_at&.>(follow.demande_seen_at) ||
+      demande = dossier.last_champ_updated_at&.>(follow.demande_seen_at) ||
+        dossier.groupe_instructeur_updated_at&.>(follow.demande_seen_at) ||
         dossier.identity_updated_at&.>(follow.demande_seen_at) ||
         false
 
-      annotations_privees = follow.dossier.champs_private.updated_since?(follow.annotations_privees_seen_at).any?
-
-      avis_notif = follow.dossier.avis.updated_since?(follow.avis_seen_at).any?
-
-      messagerie = dossier.commentaires
-        .where.not(email: OLD_CONTACT_EMAIL)
-        .where.not(email: CONTACT_EMAIL)
-        .updated_since?(follow.messagerie_seen_at).any?
+      annotations_privees = dossier.last_champ_private_updated_at&.>(follow.annotations_privees_seen_at) || false
+      avis_notif = dossier.last_avis_updated_at&.>(follow.avis_seen_at) || false
+      messagerie = dossier.last_commentaire_updated_at&.>(follow.messagerie_seen_at) || false
 
       annotations_hash(demande, annotations_privees, avis_notif, messagerie)
     else
diff --git a/spec/models/instructeur_spec.rb b/spec/models/instructeur_spec.rb
index f1f8b95af..249554774 100644
--- a/spec/models/instructeur_spec.rb
+++ b/spec/models/instructeur_spec.rb
@@ -196,7 +196,10 @@ describe Instructeur, type: :model do
     end
 
     context 'when there is a modification on public champs' do
-      before { dossier.champs_public.first.update_attribute('value', 'toto') }
+      before {
+        dossier.champs_public.first.update(value: 'toto')
+        dossier.update(last_champ_updated_at: Time.zone.now)
+      }
 
       it { is_expected.to match({ demande: true, annotations_privees: false, avis: false, messagerie: false }) }
     end
@@ -215,20 +218,29 @@ describe Instructeur, type: :model do
     end
 
     context 'when there is a modification on private champs' do
-      before { dossier.champs_private.first.update_attribute('value', 'toto') }
+      before {
+        dossier.champs_private.first.update(value: 'toto')
+        dossier.update(last_champ_private_updated_at: Time.zone.now)
+      }
 
       it { is_expected.to match({ demande: false, annotations_privees: true, avis: false, messagerie: false }) }
     end
 
     context 'when there is a modification on avis' do
-      before { create(:avis, dossier: dossier) }
+      before {
+        create(:avis, dossier: dossier)
+        dossier.update(last_avis_updated_at: Time.zone.now)
+      }
 
       it { is_expected.to match({ demande: false, annotations_privees: false, avis: true, messagerie: false }) }
     end
 
     context 'messagerie' do
       context 'when there is a new commentaire' do
-        before { create(:commentaire, dossier: dossier, email: 'a@b.com') }
+        before {
+          create(:commentaire, dossier: dossier, email: 'a@b.com')
+          dossier.update(last_commentaire_updated_at: Time.zone.now)
+        }
 
         it { is_expected.to match({ demande: false, annotations_privees: false, avis: false, messagerie: true }) }
       end