diff --git a/lib/pleroma/object/fetcher.ex b/lib/pleroma/object/fetcher.ex
index c76974adc..a9e6e508c 100644
--- a/lib/pleroma/object/fetcher.ex
+++ b/lib/pleroma/object/fetcher.ex
@@ -182,6 +182,10 @@ def fetch_object_from_id(id, options \\ []) do
         log_fetch_error(id, e)
         {:reject, reason}
 
+      {:transmogrifier, {:error, reason}} = e ->
+        log_fetch_error(id, e)
+        {:error, reason}
+
       {:transmogrifier, reason} = e ->
         log_fetch_error(id, e)
         {:error, reason}
diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 55985d310..f6d2ea652 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -686,6 +686,16 @@ defp handle_incoming_normalised(
     end
   end
 
+  defp handle_incoming_normalised(
+         %{
+           "type" => "Undo",
+           "object" => %{"type" => "Delete"}
+         },
+         _options
+       ) do
+    {:error, :unsupported}
+  end
+
   # For Undos that don't have the complete object attached, try to find it in our database.
   defp handle_incoming_normalised(
          %{
@@ -727,7 +737,7 @@ defp handle_incoming_normalised(
     end
   end
 
-  defp handle_incoming_normalised(_, _), do: :error
+  defp handle_incoming_normalised(_, _), do: {:error, :unsupported}
 
   @spec get_obj_helper(String.t(), Keyword.t()) :: {:ok, Object.t()} | nil
   def get_obj_helper(id, options \\ []) do
diff --git a/lib/pleroma/workers/receiver_worker.ex b/lib/pleroma/workers/receiver_worker.ex
index a8ea86eae..9980a3546 100644
--- a/lib/pleroma/workers/receiver_worker.ex
+++ b/lib/pleroma/workers/receiver_worker.ex
@@ -43,6 +43,10 @@ def perform(%Job{args: %{"op" => "incoming_ap_doc", "params" => params}}) do
       {:error, :ignore} ->
         {:cancel, :ignore}
 
+      {:error, :unsupported} ->
+        Logger.info("Received unsupported action: #{inspect(params)}")
+        {:cancel, :unsupported}
+
       # invalid data or e.g. deleting an object we don't know about anyway
       {:error, {:validate, issue}} ->
         Logger.info("Received invalid AP document: #{inspect(issue)}")