whats the difference and reason for 2 email scans?

Ok I have email scanning turned on.

I have it turned on in both scanning pop3/s port as well as the other options that can be set in outlook.

Recently I had a weird problem where a friend reinstalled his email server and since then nod32 can not talk to it over ssl so I disabled nod32 pop3s scanning.

I noticed however I am still seeing emails scanned.

Is it now scanning email's when I click on them? (I notice a delay now)
Is it less secure scanning email's on demand after they downloaded than over the ports?
When I scan over the port's does it stop it scanning a 2nd time inside outlook after download?