Canadian immigration finally amended Immigration Regulations in respect to the definition of dependent child.
Starting August 1st, 2014 the definition of dependent child will be as follows:
(b) is in one of the following situations of dependency, namely,
(i) is less than 19 years of age and is not a spouse or common-law partner, or
(ii) is 19 years of age or older and has depended substantially on the financial support of the parent since before the age of 19 and is unable to be financially self-supporting due to a physical or mental condition.
As you can see the allowance for the full-time student has been removed from Regulations, so the only above definition will apply from August 2014.
But this time the government also included in amended Regulations the new provision for so called "lock-in date" for the age of dependent child. The old provision stated that the child remains the dependent child until visas are granted providing that such child met the definition at the time the federal PR application was submitted.
New amended Regulations expand the "lock-in age" provision to provincial nominees as well - thus starting August 2014 the child will continue to be a dependent child as long as such child met the definition of dependent child on the date the PNP nomination application was made, regardless how old is the child when nomination is granted and federal PR application is filed.