diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index aafd4a9f3..62072b3ae 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -6,6 +6,12 @@ snovault
 Change Log
 ----------
 
+11.23.0
+=======
+* 2024-11-02/dmichaels
+  - Fix for unexpected 'sid' indexing problem.
+
+
 11.22.0
 =======
 * 2024-09-03/dmichaels
diff --git a/pyproject.toml b/pyproject.toml
index ad8bb4f73..7ec98d2d3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "dcicsnovault"
-version = "11.22.0"
+version = "11.23.0"
 description = "Storage support for 4DN Data Portals."
 authors = ["4DN-DCIC Team <support@4dnucleome.org>"]
 license = "MIT"
diff --git a/snovault/storage.py b/snovault/storage.py
index 556e718c2..9cb45d3e9 100644
--- a/snovault/storage.py
+++ b/snovault/storage.py
@@ -1,4 +1,5 @@
 import boto3
+from copy import deepcopy
 import structlog
 import uuid
 
@@ -566,8 +567,15 @@ def revision_history(self, *, rid):
         session = self.DBSession
         revisions = []
         for revision in session.query(PropertySheet).filter_by(rid=rid).order_by(PropertySheet.sid):
-            revision.properties['sid'] = revision.sid
-            revisions.append(revision.properties)
+            # 2024-11-04/C4-1188/PR-306/dmichaels:
+            # Fix for "sid" appearing in properties in some situations, and ultimately ending up
+            # with validation-errors = Additional properties are not allowed ('sid' was unexpected).
+            # See smaht-portal/.../test_types_file.py for 92e8371b-bcdf-44de-ad49-3a5f108e91eb (from workbook-inserts).
+            # revision.properties['sid'] = revision.sid
+            # revisions.append(revision.properties)
+            revision_properties = deepcopy(revision.properties)
+            revision_properties['sid'] = revision.sid
+            revisions.append(revision_properties)
         return revisions