Undefined index i FileJournal

Zdravím narazil jsem na chybu:

exception 'ErrorException' with message 'Undefined index: i' in /var/www/vendor/nette/caching/src/Caching/Storages/FileJournal.php:728
Stack trace:
#0 /var/www/vendor/nette/caching/src/Caching/Storages/FileJournal.php(728): Tracy\Debugger::_errorHandler(8, 'Undefined index...', '/var/www/vendor...', 728, Array)
#1 /var/www/vendor/nette/caching/src/Caching/Storages/FileJournal.php(694): Nette\Caching\Storages\FileJournal->prepareNode(0, Array)
#2 /var/www/vendor/nette/caching/src/Caching/Storages/FileJournal.php(268): Nette\Caching\Storages\FileJournal->commit()
#3 /var/www/vendor/nette/caching/src/Caching/Storages/MemcachedStorage.php(186): Nette\Caching\Storages\FileJournal->clean(Array)
#4 /var/www/vendor/nette/caching/src/Caching/Cache.php(201): Nette\Caching\Storages\MemcachedStorage->clean(Array)
#5 /var/www/app/Model/Exsys/Categories/CategoriesFacade.php(235): Nette\Caching\Cache->clean(Array)
#6 /var/www/app/Web1localhostModule/ShopModule/presenters/CategoriesPresenter.php(48): Exsys\Categories\CategoriesFacade->create(Array)
#7 [internal function]: Web1localhostModule\ShopModule\CategoriesPresenter->actionNew()
#8 /var/www/vendor/nette/application/src/Application/UI/PresenterComponent.php(90): ReflectionMethod->invokeArgs(Object(Web1localhostModule\ShopModule\CategoriesPresenter), Array)
#9 /var/www/vendor/nette/application/src/Application/UI/Presenter.php(191): Nette\Application\UI\PresenterComponent->tryCall('actionnew', Array)
#10 /var/www/vendor/nette/application/src/Application/Application.php(149): Nette\Application\UI\Presenter->run(Object(Nette\Application\Request))
#11 /var/www/vendor/nette/application/src/Application/Application.php(88): Nette\Application\Application->processRequest(Object(Nette\Application\Request))
#12 /var/www/app/bootstrap.php(94): Nette\Application\Application->run()
#13 /var/www/subdomains/www/index.php(17): require('/var/www/app/bo...')
#14 {main}
(stored in /var/www/app/log/exception-2014-09-12-15-10-18-e4651fd05a8f72b4e49a880301395df7.html)

začlo se to objevovat z ničeho nic ani mě nenapadá co by to mohlo způsobovat. Argumenty jsou v pořádku.