diff --git a/src/documents/serialisers.py b/src/documents/serialisers.py
index 6f9e4a48f..eaf2cde83 100644
--- a/src/documents/serialisers.py
+++ b/src/documents/serialisers.py
@@ -1789,12 +1789,6 @@ class EditPdfDocumentsSerializer(DocumentListSerializer, SourceModeValidationMix
                     "update_document only allowed with a single output document",
                 )
 
-        if any(
-            op.get("doc", 0) < 0 or op.get("doc", 0) >= len(operations)
-            for op in operations
-        ):
-            raise serializers.ValidationError("doc index is out of bounds")
-
         doc = Document.objects.get(id=documents[0])
         if doc.page_count:
             for op in operations:
@@ -2159,12 +2153,6 @@ class BulkEditSerializer(
                     "update_document only allowed with a single output document",
                 )
 
-        if any(
-            op.get("doc", 0) < 0 or op.get("doc", 0) >= len(parameters["operations"])
-            for op in parameters["operations"]
-        ):
-            raise serializers.ValidationError("doc index is out of bounds")
-
         doc = Document.objects.get(id=document_id)
         # doc existence is already validated
         if doc.page_count:
diff --git a/src/documents/tests/test_api_bulk_edit.py b/src/documents/tests/test_api_bulk_edit.py
index 436208d3a..59c872939 100644
--- a/src/documents/tests/test_api_bulk_edit.py
+++ b/src/documents/tests/test_api_bulk_edit.py
@@ -1769,7 +1769,14 @@ class TestBulkEditAPI(DirectoriesMixin, APITestCase):
         self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
         self.assertIn(b"valid integer is required", response.content)
 
-        for doc_index in (-1, 2**32):
+        # A negative doc index is rejected by PdfEditOperationSerializer's
+        # own min_value=0 field constraint, before the "doc index is out
+        # of bounds" object-level check (against len(operations)) ever
+        # runs -- hence the different expected message per case.
+        for doc_index, expected_message in (
+            (-1, b"greater than or equal to 0"),
+            (2**32, b"doc index is out of bounds"),
+        ):
             with self.subTest(doc_index=doc_index):
                 response = self.client.post(
                     "/api/documents/edit_pdf/",
@@ -1782,7 +1789,7 @@ class TestBulkEditAPI(DirectoriesMixin, APITestCase):
                     content_type="application/json",
                 )
                 self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
-                self.assertIn(b"doc index is out of bounds", response.content)
+                self.assertIn(expected_message, response.content)
 
         response = self.client.post(
             "/api/documents/edit_pdf/",