diff --git a/biscuit/apps/alsijil/views.py b/biscuit/apps/alsijil/views.py
index 9df61b1ac51148ea3575069d01c7edb5124e7779..2df8ebf24fb6413b93d1793d23f88750320ae045 100644
--- a/biscuit/apps/alsijil/views.py
+++ b/biscuit/apps/alsijil/views.py
@@ -99,12 +99,11 @@ def group_week(request: HttpRequest, week: Optional[int] = None) -> HttpResponse
     periods_by_day_unsorted = {}
     if group:
         for act_group in [group] + list(group.child_groups.all()):
-            for lesson in act_group.lessons.prefetch_related(
-                'lesson_period',
-                'lesson_period__period',
-                'lesson_period__period__lesson__teachers'
-            ).filter(date_start__lte=week_start, date_end__gte=week_end):
-                for lesson_period in lesson.lesson_periods.all():
+            for lesson in act_group.lessons.filter(date_start__lte=week_start, date_end__gte=week_end):
+                for lesson_period in lesson.lesson_periods.select_related(
+                    'period',
+                    'period__lesson__teachers'
+                ).all():
                     periods_by_day_unsorted.setdefault(
                         lesson_period.period.weekday, []).append(lesson_period)