diff --git a/judge/admin/problem.py b/judge/admin/problem.py
index 1a47d37..7f0e473 100644
--- a/judge/admin/problem.py
+++ b/judge/admin/problem.py
@@ -33,6 +33,7 @@ from judge.widgets import (
     CheckboxSelectMultipleWithSelectAll,
     HeavyPreviewAdminPageDownWidget,
 )
+from judge.utils.problems import user_editable_ids, user_tester_ids
 
 MEMORY_UNITS = (("KB", "KB"), ("MB", "MB"))
 
@@ -359,12 +360,31 @@ class ProblemAdmin(CompareVersionAdmin):
             self._rescore(request, obj.id)
 
     def save_related(self, request, form, formsets, change):
+        editors = set()
+        testers = set()
+        if "curators" in form.changed_data or "authors" in form.changed_data:
+            editors = set(form.instance.editor_ids)
+        if "testers" in form.changed_data:
+            testers = set(form.instance.tester_ids)
+
         super().save_related(request, form, formsets, change)
-        # Only rescored if we did not already do so in `save_model`
         obj = form.instance
         obj.curators.add(request.profile)
         obj.is_organization_private = obj.organizations.count() > 0
         obj.save()
+
+        if "curators" in form.changed_data or "authors" in form.changed_data:
+            del obj.editor_ids
+            editors = editors.union(set(obj.editor_ids))
+        if "testers" in form.changed_data:
+            del obj.tester_ids
+            testers = testers.union(set(obj.tester_ids))
+
+        for editor in editors:
+            user_editable_ids.dirty(editor)
+        for tester in testers:
+            user_tester_ids.dirty(tester)
+
         # Create notification
         if "is_public" in form.changed_data or "organizations" in form.changed_data:
             users = set(obj.authors.all())
diff --git a/judge/caching.py b/judge/caching.py
index 8f42d24..43479da 100644
--- a/judge/caching.py
+++ b/judge/caching.py
@@ -40,12 +40,10 @@ def cache_wrapper(prefix, timeout=None):
     def _get(key):
         if not l0_cache:
             return cache.get(key)
-        print("GET", key, l0_cache.get(key))
         return l0_cache.get(key) or cache.get(key)
 
     def _set_l0(key, value):
         if l0_cache:
-            print("SET", key, value)
             l0_cache.set(key, value, 30)
 
     def _set(key, value, timeout):
diff --git a/judge/models/problem.py b/judge/models/problem.py
index 3377b2d..baed1d8 100644
--- a/judge/models/problem.py
+++ b/judge/models/problem.py
@@ -436,15 +436,23 @@ class Problem(models.Model, PageVotable, Bookmarkable):
 
     @cached_property
     def author_ids(self):
-        return self.authors.values_list("id", flat=True)
+        return Problem.authors.through.objects.filter(problem=self).values_list(
+            "profile_id", flat=True
+        )
 
     @cached_property
     def editor_ids(self):
-        return self.author_ids | self.curators.values_list("id", flat=True)
+        return self.author_ids.union(
+            Problem.curators.through.objects.filter(problem=self).values_list(
+                "profile_id", flat=True
+            )
+        )
 
     @cached_property
     def tester_ids(self):
-        return self.testers.values_list("id", flat=True)
+        return Problem.testers.through.objects.filter(problem=self).values_list(
+            "profile_id", flat=True
+        )
 
     @cached_property
     def usable_common_names(self):
diff --git a/judge/utils/problems.py b/judge/utils/problems.py
index 5861fa7..67ef163 100644
--- a/judge/utils/problems.py
+++ b/judge/utils/problems.py
@@ -10,8 +10,6 @@ from django.db.models import Case, Count, ExpressionWrapper, F, Max, Q, When
 from django.db.models.fields import FloatField
 from django.utils import timezone
 from django.utils.translation import gettext as _, gettext_noop
-from django.db.models.signals import pre_save
-from django.dispatch import receiver
 
 from judge.models import Problem, Submission
 from judge.ml.collab_filter import CollabFilter
@@ -29,9 +27,9 @@ __all__ = [
 @cache_wrapper(prefix="user_tester")
 def user_tester_ids(profile):
     return set(
-        Problem.testers.through.objects.filter(profile=profile).values_list(
-            "problem_id", flat=True
-        )
+        Problem.testers.through.objects.filter(profile=profile)
+        .values_list("problem_id", flat=True)
+        .distinct()
     )
 
 
@@ -41,7 +39,9 @@ def user_editable_ids(profile):
         (
             Problem.objects.filter(authors=profile)
             | Problem.objects.filter(curators=profile)
-        ).values_list("id", flat=True)
+        )
+        .values_list("id", flat=True)
+        .distinct()
     )
     return result
 
@@ -249,22 +249,3 @@ def finished_submission(sub):
         keys += ["contest_complete:%d" % participation.id]
         keys += ["contest_attempted:%d" % participation.id]
     cache.delete_many(keys)
-
-
-@receiver([pre_save], sender=Problem)
-def on_problem_save(sender, instance, **kwargs):
-    if instance.id is None:
-        return
-    prev_editors = list(sender.objects.get(id=instance.id).editor_ids)
-    new_editors = list(instance.editor_ids)
-    if prev_editors != new_editors:
-        all_editors = set(prev_editors + new_editors)
-        for profile_id in all_editors:
-            user_editable_ids.dirty(profile_id)
-
-    prev_testers = list(sender.objects.get(id=instance.id).tester_ids)
-    new_testers = list(instance.tester_ids)
-    if prev_testers != new_testers:
-        all_testers = set(prev_testers + new_testers)
-        for profile_id in all_testers:
-            user_tester_ids.dirty(profile_id)