XF 1.5 Duplicate entry 'usernamehere' for key 'username'

[Maester Aemon]

Hi. I am getting mysqli error multiple times here is the error.

Error Info
Zend_Db_Statement_Mysqli_Exception: Mysqli statement execute error : Duplicate entry 'ckyablyat6996' for key 'username' - library/Zend/Db/Statement/Mysqli.php:214
Generated By: Unknown Account, 3 minutes ago
Stack Trace
#0 /public/library/Zend/Db/Statement.php(297): Zend_Db_Statement_Mysqli->_execute(Array)
#1 /public/library/Zend/Db/Adapter/Abstract.php(479): Zend_Db_Statement->execute(Array)
#2 /public/library/Zend/Db/Adapter/Abstract.php(574): Zend_Db_Adapter_Abstract->query('INSERT INTO `xf...', Array)
#3 /public/library/XenForo/DataWriter.php(1638): Zend_Db_Adapter_Abstract->insert('xf_user', Array)
#4 /home/nginx/domains/domain/public/library/XenForo/DataWriter.php(1627): XenForo_DataWriter->_insert()
#5 /home/nginx/domains/domain/public/library/XenForo/DataWriter.php(1419): XenForo_DataWriter->_save()
#6 /public/library/XenForo/ControllerPublic/Register.php(416): XenForo_DataWriter->save()
#7 /public/library/XenForo/FrontController.php(351): XenForo_ControllerPublic_Register->actionRegister()
#8 /public/library/XenForo/FrontController.php(134): XenForo_FrontController->dispatch(Object(XenForo_RouteMatch))
#9 /public/index.php(13): XenForo_FrontController->run()
#10 {main}
Request State
array(3) {
  ["url"] => string(46) "domain/register/register"
  ["_GET"] => array(1) {
    ["/register/register"] => string(0) ""
  }
  ["_POST"] => array(17) {
    ["username"] => string(0) ""

{USER INFO HERE}

  }
}

 

[Daniel Hood]

Well, XenMods.com doesn't get a ton of registrations but I feel like I get enough to where this would have happened at least once if UserEss was involved.

You see User Essentials in the stack trace because it does extend XenForo_ControllerPublic_Register->actionRegister(). Line 68 is the only call to parent::actionRegister(); in the function (if there were two parent::actionRegister() calls or something it'd explain the issue).

If it's happening 10-20% of the time, the easiest way to tell if it's the issue is to disable it and wait for 20 registrations to come through, at least one of them should error (5%).

I also doubt it's an issue with User Essentials because @Maester Aemon didn't include it in their add-on list and is claiming to experience the issue as well.