Ok, so since it is working fine on my sites, I don’t have a clue what is going on. If someone wants to try to debug it, here are a few suggestions:
Add the line
print_r($_SESSION['wfcart']);
to scabn.php — this will print at the top of the page the contents of the session, which is where the shopping cart contents are stored. This will confirm that going to the checkout page is wiping the cart contents rather than something else affecting the fine cart. Also, you can use this to check if the shopping carts get edited (emptied) from any other pages.
Next, try changing the shortcode on the checkout page from [scabn] to [donothing] and see if making that page not a checkout page ‘fixed’ it, i.e. you can now go to the checkout page and the cart doesn’t get emptied (granted, it won’t be a checkout page).
Assuming that stops the cart getting emptied, change the short code back to [scabn]. Then take a look at the file classes/backend.php — there is a function shortcodes($attrs). Look at the function and start commenting out lines to see what part(s) are causing the problem.
