diff --git a/swift/container/sharder.py b/swift/container/sharder.py
index adff1df977..b24adbad73 100644
--- a/swift/container/sharder.py
+++ b/swift/container/sharder.py
@@ -2396,7 +2396,7 @@ class ContainerSharder(ContainerSharderConf, ContainerReplicator):
                                       'state')
                     self.logger.timing_since(
                         'sharder.sharding.completed',
-                        broker.get_own_shard_range().epoch)
+                        float(broker.get_own_shard_range().epoch))
                 else:
                     self.info(broker, 'Completed cleaving, DB remaining in '
                                       'sharding state')
diff --git a/test/unit/container/test_sharder.py b/test/unit/container/test_sharder.py
index 76387d1379..e809858ddc 100644
--- a/test/unit/container/test_sharder.py
+++ b/test/unit/container/test_sharder.py
@@ -2476,6 +2476,9 @@ class TestSharder(BaseTestSharder):
         self.assertEqual('sharder.sharding.cleave',
                          self.logger.log_dict['timing_since'][-1][0][0])
         self.assertGreater(self.logger.log_dict['timing_since'][-1][0][1], 0)
+        for call in self.logger.log_dict['timing_since']:
+            self.assertNotIsInstance(call[0][1], Timestamp)
+            self.assertIsInstance(call[0][1], float)
         lines = sharder.logger.get_lines_for_level('info')
         self.assertEqual(
             ["Kick off container cleaving, own shard range in state "
@@ -2534,6 +2537,9 @@ class TestSharder(BaseTestSharder):
         self.assertEqual('sharder.sharding.send_sr',
                          self.logger.log_dict['timing_since'][-1][0][0])
         self.assertGreater(self.logger.log_dict['timing_since'][-1][0][1], 0)
+        for call in self.logger.log_dict['timing_since']:
+            self.assertNotIsInstance(call[0][1], Timestamp)
+            self.assertIsInstance(call[0][1], float)
 
     def test_cleave_timing_metrics(self):
         broker = self._make_broker()