diff --git a/google/cloud/bigquery/job/query.py b/google/cloud/bigquery/job/query.py
index e45a46894..83d2751ce 100644
--- a/google/cloud/bigquery/job/query.py
+++ b/google/cloud/bigquery/job/query.py
@@ -1409,9 +1409,9 @@ def _reload_query_results(
         # Python_API_core, as part of a major rewrite of the deadline, timeout,
         # retry process sets the timeout value as a Python object().
         # Our system does not natively handle that and instead expects
-        # either none or a numeric value. If passed a Python object, convert to
+        # either None or a numeric value. If passed a Python object, convert to
         # None.
-        if isinstance(self._done_timeout, object):  # pragma: NO COVER
+        if type(self._done_timeout) is object:  # pragma: NO COVER
             self._done_timeout = None
 
         if self._done_timeout is not None:  # pragma: NO COVER