diff --git a/src/python/pcp/pmsubsys.py b/src/python/pcp/pmsubsys.py
index 1964b909f..643f505c1 100644
--- a/src/python/pcp/pmsubsys.py
+++ b/src/python/pcp/pmsubsys.py
@@ -173,7 +173,7 @@ def get_stats(self, pcp):
 
         try:
             metric_result = pcp.pmFetch(self.metric_pmids)
-            self._timestamp = metric_result.contents.timestamp
+            self._timestamp = copy.deepcopy(metric_result.contents.timestamp)
         except pmErr as e:
             self._timestamp = timeval(0, 0)
             raise e