I had a problem with my previous helmet (HTC IS-16) where it would fog up, even with a Pinlock insert. The biggest trouble was as soon as you opened the visor to clear the fog, rain ran down the INSIDE of the visor.
I 'upgraded' to an Arai Axcess in the summer and only recently (this mornnig) rode in the rain to discover exactly the same fault.
I say "fault", because in my opinion it makes the helmet unfit for purpose and dangerous. Once water has run down the inside of the visor, not only is your vision seriously impaired, but any anti-fog coating including a PinLock is ruined until you can stop and dry/air it.
I can see from the design of both helmets why it happens.
1.) There is no gutter along the top of the visor seal.
2.) There is a gap above the visor seal between the visor and the helmet surface that creates a captive area where water will collect when the visor is shut.
3.) The instant the visor seal is broken, due to the above, water will cascade down the inside.
It is very difficult to wipe the water away, there is no wind to blow it clear either.
I'm looking for suggestions on how to live with the helmet until I can either get my money back or otherwise get a better helmet!