I received a report from a user today that users in Chrome cannot add items to their cart. It seems to be a new problem only in the past few days, perhaps caused by a recent Chrome update.
I later discovered that this is only a chrome problem, and doesn't actually affect Firefox users at all.
Basically, in Chrome, the user clicks the add to cart button, the site redirects to the cart, and the cart is empty.
When I inspected the HTTP requests for both Chrome and Firefox, I noticed that in Firefox, the exp_cartthrob_session_id cookie is maintained throughout the session. In Chrome, it seems to be reset on each request. Basically each request (GET product details page, POST add to cart, GET cart page) comes with a separate header that looks like:
Set-Cookie:exp_cartthrob_session_id=abcdefghijklmnopqrstuvwxyz; expires=Wed, 03-Sep-2014 03:17:59 GMT; Max-Age=18000; path=/
Why would Cartthrob be resetting the session header on every request. Is this a bug with Chrome expiring cookies, or a bug with Cartthrob? How can I get "add to cart" working again on my site?