diff --git a/src/applications/differential/controller/DifferentialController.php b/src/applications/differential/controller/DifferentialController.php
--- a/src/applications/differential/controller/DifferentialController.php
+++ b/src/applications/differential/controller/DifferentialController.php
@@ -190,6 +190,12 @@
       }
     }
 
+    // Cast duration to a float since it used to be a string in some
+    // cases.
+    if (isset($map['duration'])) {
+      $map['duration'] = (double)$map['duration'];
+    }
+
     return $map;
   }
 
diff --git a/src/applications/differential/controller/DifferentialRevisionViewController.php b/src/applications/differential/controller/DifferentialRevisionViewController.php
--- a/src/applications/differential/controller/DifferentialRevisionViewController.php
+++ b/src/applications/differential/controller/DifferentialRevisionViewController.php
@@ -1078,6 +1078,10 @@
       return null;
     }
 
+    if (!$diff->getBuildable()) {
+      return null;
+    }
+
     $interesting_messages = array();
     foreach ($diff->getUnitMessages() as $message) {
       switch ($message->getResult()) {