diff --git a/basyx/aas/adapter/xml/xml_deserialization.py b/basyx/aas/adapter/xml/xml_deserialization.py
index b5899c9fd..e42a9a6f6 100644
--- a/basyx/aas/adapter/xml/xml_deserialization.py
+++ b/basyx/aas/adapter/xml/xml_deserialization.py
@@ -87,7 +87,7 @@ def _tag_replace_namespace(tag: str, nsmap: Dict[str, str]) -> str:
     """
     split = tag.split("}")
     for prefix, namespace in nsmap.items():
-        if namespace == split[0][1:]:
+        if prefix and namespace == split[0][1:]:
             return prefix + ":" + split[1]
     return tag
 
diff --git a/test/adapter/xml/test_xml_deserialization.py b/test/adapter/xml/test_xml_deserialization.py
index f562e02a6..9310e4462 100644
--- a/test/adapter/xml/test_xml_deserialization.py
+++ b/test/adapter/xml/test_xml_deserialization.py
@@ -221,7 +221,7 @@ def test_operation_variable_no_submodel_element(self) -> None:
             </aas:submodel>
         </aas:submodels>
         """)
-        self._assertInExceptionAndLog(xml, "aas:value", KeyError, logging.ERROR)
+        self._assertInExceptionAndLog(xml, ["aas:value", "has no submodel element"], KeyError, logging.ERROR)
 
     def test_operation_variable_too_many_submodel_elements(self) -> None:
         # TODO: simplify this should our suggestion regarding the XML schema get accepted
@@ -256,6 +256,7 @@ def test_operation_variable_too_many_submodel_elements(self) -> None:
         with self.assertLogs(logging.getLogger(), level=logging.WARNING) as context:
             read_aas_xml_file(io.BytesIO(xml.encode("utf-8")), failsafe=False)
         self.assertIn("aas:value", context.output[0])  # type: ignore
+        self.assertIn("more than one submodel element", context.output[0])
 
     def test_duplicate_identifier(self) -> None:
         xml = _xml_wrap("""
@@ -306,7 +307,7 @@ def get_clean_store() -> model.DictObjectStore:
         with self.assertLogs(logging.getLogger(), level=logging.INFO) as log_ctx:
             identifiers = read_aas_xml_file_into(object_store, bytes_io, replace_existing=False, ignore_existing=True)
         self.assertEqual(len(identifiers), 0)
-        self.assertIn("already exists in the object store", log_ctx.output[0])  # type: ignore
+        self.assertIn("already exists in the object store", log_ctx.output[0])
         submodel = object_store.pop()
         self.assertIsInstance(submodel, model.Submodel)
         self.assertEqual(submodel.id_short, "test123")