diff --git a/gwcs/converters/wcs.py b/gwcs/converters/wcs.py
index bfaab5bd..96f1a94e 100644
--- a/gwcs/converters/wcs.py
+++ b/gwcs/converters/wcs.py
@@ -1,7 +1,9 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
 # -*- coding: utf-8 -*-
 
+from ast import Attribute
 import warnings
+from contextlib import suppress
 from asdf.extension import Converter
 
 
@@ -22,7 +24,7 @@ def from_yaml_tree(self, node, tag, ctx):
 
         # Ignore the warning about the bounding box order for data read from a
         # file. This is causing issues with files from MAST.
-        with warnings.catch_warnings():
+        with suppress(AttributeError), warnings.catch_warnings():
             warnings.filterwarnings('ignore', category=GwcsBoundingBoxWarning)
             _ = gwcsobj.bounding_box