I think I'm experiencing the same thing Daniel F is reporting, I have experienced this twice when logging into an expired session with the login logs in view. This is what appears in the System Logs of IPS:
"The log entry was triggered by a guest"
Error: Call to a member function inGroup() on array (0)
#0 /var/www/html/hvportal/init.php(442) : eval()'d code(26): IPS\loginlogs_hook_logs->log('GUEST', Array)
#1 /var/www/html/hvportal/applications/core/modules/admin/system/login.php(52): IPS\loginlogs_hook_logs->authenticate()
#2 /var/www/html/hvportal/system/Dispatcher/Controller.php(96): IPS\core\modules\admin\system\_login->manage()
#3 /var/www/html/hvportal/system/Dispatcher/Dispatcher.php(129): IPS\Dispatcher\_Controller->execute()
#4 /var/www/html/hvportal/admin/index.php(13): IPS\_Dispatcher->run()
#5 {main}
Backtrace:
#0 /var/www/html/hvportal/init.php(506): IPS\_Log::log('Error: Call to ...', 'uncaught_except...')
#1 [internal function]: IPS\IPS::exceptionHandler(Object(Error))
#2 {main}