The library is modifying the content of payload just because the content has something that can taken by UUID class. This is failing the schema validation down the road. The location of the culprit https://github.com/microsoft/kiota-python/blob/8740fcb17ddc2e943baaecfaba98bfef97ef920a/packages/serialization/json/kiota_serialization_json/json_parse_node.py#L331