diff --git a/dapr/serializers/json.py b/dapr/serializers/json.py
index 59e1c194b..e0480667a 100644
--- a/dapr/serializers/json.py
+++ b/dapr/serializers/json.py
@@ -101,7 +101,12 @@ def __init__(self, *args, **kwargs):
     def custom_scanstring(cls, s, end, strict=True):
         (s, end) = json.decoder.scanstring(s, end, strict)  # type: ignore
         if cls.datetime_regex.match(s):
-            return (parser.parse(s), end)
+            # The regex only checks the prefix, so a string such as
+            # '2024-01-01 notes' reaches the parser; keep it as a string.
+            try:
+                return (parser.parse(s), end)
+            except (ValueError, OverflowError):
+                return (s, end)
 
         duration = DAPR_DURATION_PARSER.match(s)
         if duration is not None and duration.lastindex is not None:
diff --git a/tests/serializers/test_default_json_serializer.py b/tests/serializers/test_default_json_serializer.py
index 8f65595c0..2ccaea86f 100644
--- a/tests/serializers/test_default_json_serializer.py
+++ b/tests/serializers/test_default_json_serializer.py
@@ -77,6 +77,14 @@ def test_deserialize(self):
             ),
         )
 
+    def test_deserialize_string_with_date_prefix(self):
+        serializer = DefaultJSONSerializer()
+        payload = b'{"note":"2024-01-01 meeting notes","file":"2024/01/01_backup.tar"}'
+
+        obj = serializer.deserialize(payload)
+        self.assertEqual(obj['note'], '2024-01-01 meeting notes')
+        self.assertEqual(obj['file'], '2024/01/01_backup.tar')
+
 
 if __name__ == '__main__':
     unittest.main()