diff --git a/bookwyrm/activitypub/base_activity.py b/bookwyrm/activitypub/base_activity.py
index 5edf3115..7ef0920f 100644
--- a/bookwyrm/activitypub/base_activity.py
+++ b/bookwyrm/activitypub/base_activity.py
@@ -177,6 +177,7 @@ def set_related_field(
         # we have to set it post-creation
         if not hasattr(model_field, 'activitypub_field'):
             setattr(item, related_field_name, instance)
+            item.save()
 
 
 def resolve_remote_id(model, remote_id, refresh=False, save=True):