Pinlock Shields and inserts

[myfirstluv]

Good morning

I have recently purchased a pinlock shield and insert. I was riding this morning 33F weather.

And I noticed the insert started to fog/mist up on the top left corner of the insert half way through a 20 minute ride.  Then slowly it fogged along the whole top edge.

Why did this happen?  I have heard such good things about it.

Has this ever happened to anyone else?

[myfirstluv]

It fogged on the outside of the insert, within the helmet.  Not in between the insert and shield.