Make 'overdue' function robust by using strtotime comparisons

CRM/Utils/Date.php

@@ -788,7 +788,7 @@ class CRM_Utils_Date {
       $now = self::isoToMysql($now);
     }
 
-    return ($mysqlDate >= $now) ? FALSE : TRUE;
+    return (strtotime($mysqlDate) >= strtotime($now)) ? FALSE : TRUE;
   }
 
   /**