diff --git a/bookwyrm/activitypub/book.py b/bookwyrm/activitypub/book.py
index 7615adcf7..538fa571e 100644
--- a/bookwyrm/activitypub/book.py
+++ b/bookwyrm/activitypub/book.py
@@ -11,6 +11,7 @@ class Book(ActivityObject):
     """ serializes an edition or work, abstract """
 
     title: str
+    lastEditedBy: str = None
     sortTitle: str = ""
     subtitle: str = ""
     description: str = ""
diff --git a/bookwyrm/models/activitypub_mixin.py b/bookwyrm/models/activitypub_mixin.py
index f687e96cb..71e02082b 100644
--- a/bookwyrm/models/activitypub_mixin.py
+++ b/bookwyrm/models/activitypub_mixin.py
@@ -148,14 +148,14 @@ class ActivitypubMixin:
         mentions = self.recipients if hasattr(self, "recipients") else []
 
         # we always send activities to explicitly mentioned users' inboxes
-        recipients = [u.inbox for u in mentions or []]
+        recipients = [u.inbox for u in mentions or [] if not u.local]
 
         # unless it's a dm, all the followers should receive the activity
         if privacy != "direct":
             # we will send this out to a subset of all remote users
             queryset = user_model.viewer_aware_objects(user).filter(
                 local=False,
-            )
+            ).distinct()
             # filter users first by whether they're using the desired software
             # this lets us send book updates only to other bw servers
             if software:
@@ -175,7 +175,7 @@ class ActivitypubMixin:
                 "inbox", flat=True
             )
             recipients += list(shared_inboxes) + list(inboxes)
-        return recipients
+        return list(set(recipients))
 
     def to_activity_dataclass(self):
         """ convert from a model to an activity """
diff --git a/bookwyrm/models/book.py b/bookwyrm/models/book.py
index a6824c0ad..5280c7aaf 100644
--- a/bookwyrm/models/book.py
+++ b/bookwyrm/models/book.py
@@ -26,7 +26,11 @@ class BookDataModel(ObjectMixin, BookWyrmModel):
         max_length=255, blank=True, null=True, deduplication_field=True
     )
 
-    last_edited_by = models.ForeignKey("User", on_delete=models.PROTECT, null=True)
+    last_edited_by = fields.ForeignKey(
+        "User",
+        on_delete=models.PROTECT,
+        null=True,
+    )
 
     class Meta:
         """ can't initialize this model, that wouldn't make sense """