I have encountered an odd problem relating to sessions on my site.

If I load up a product page from a shortcut and click "Add to Cart" the product does not get added to the cart (as a session variable) - it say's the cart is still empty. If I go back and try again it will now work. Also, if I view one page (any page) before viewing the product page and then click "Add to Cart" it is recorded fine.

It appears that my session is only being activated after one page refresh - not on the initially loaded page. Is there a server setting or some thing that I could have overlooked to cause this or is it more likely that my cart adding code is wrong?

Thanks