Don't use nested forms
HTML doesn't allow nested forms, so you shouldn't use them in primefaces either.They can cause undesired behavior.
See: other stackoverflow questions, or a nice collection of things to avoid in JSF: here (note point 2)
This is the only problem I see in your code. Other than that in rare cases you might have problems if using ajax and not processing the whole form. But as I can see this is not the case in your code.