If a candidate has registered for state quota counselling but NOT in AIQ counselling, are there any risks of it. (if any please tell).

Hello aspirant !!

There is no such rule that you should apply for All India Quota in order to be eligible for State Quota .Thus, it is not necessary to apply . It is the complete choice of the individual candidate .
Speaking of the risks, please consider the following situations.
1) You want a good  government college in a state for which you don't have a domicile AIQ is the option.
2)You didn't score well for a college in your state but your marks were enough to ensure you a seat in a college in some other state , as cut off is different for different colleges.

If such conditions arise, then not applying to AIQ will be a bad decision.

All the best.
Hope this helps .