I saw quite a few of these in my error logs.
Code:
#0 /var/www/skial.com/library/Zend/Db/Statement.php(297): Zend_Db_Statement_Mysqli->_execute(Array)
#1 /var/www/skial.com/library/Zend/Db/Adapter/Abstract.php(479): Zend_Db_Statement->execute(Array)
#2 /var/www/skial.com/library/Zend/Db/Adapter/Abstract.php(574): Zend_Db_Adapter_Abstract->query('INSERT INTO `xf...', Array)
#3 /var/www/skial.com/library/XenForo/Model/Ip.php(62): Zend_Db_Adapter_Abstract->insert('xf_ip', Array)
#4 /var/www/skial.com/library/XenForo/Model/Ip.php(76): XenForo_Model_Ip->logIp(1494, 'post', 51922, 'insert', NULL, NULL)
#5 /var/www/skial.com/library/XenForo/DataWriter/DiscussionMessage.php(568): XenForo_Model_Ip::log(1494, 'post', 51922, 'insert', NULL)
#6 /var/www/skial.com/library/XenForo/DataWriter/DiscussionMessage.php(477): XenForo_DataWriter_DiscussionMessage->_updateIpData()
#7 /var/www/skial.com/library/XenForo/DataWriter.php(1385): XenForo_DataWriter_DiscussionMessage->_postSave()
#8 /var/www/skial.com/library/XenForo/ControllerPublic/Thread.php(505): XenForo_DataWriter->save()
#9 /var/www/skial.com/library/XenForo/FrontController.php(310): XenForo_ControllerPublic_Thread->actionAddReply()
#10 /var/www/skial.com/library/XenForo/FrontController.php(132): XenForo_FrontController->dispatch(Object(XenForo_RouteMatch))
#11 /var/www/skial.com/index.php(13): XenForo_FrontController->run()
#12 {main}