Start workflow on task create

I have a list A. When item created in this list workflow start a task processe and as a result create task item in task list (B). On task B i have workflow, wich i want to update newly created task item and update some fields in this task. But for some reason workflow on task list not starting if task was created from workflow on list A. only when i create task manualy. I checked that "Created By" field in task list is no a system user and workflow in task list have "Start on create".