Previous Users CANNOT Checkout - Logs them out

-- url of the page with the problem -- : www.stacecosmetics.com/
-- HikaShop version -- : 2.2.2 (updated again today)
-- Joomla version -- : 2.5.16
-- PHP version -- : 5.3.26
-- Browser(s) name and version -- : Various browsers and platforms (same problem)
-- Error-message(debug-mod must be tuned on) -- : none

This problem is very similar to:
www.hikashop.com/forum/checkout/863830-s...post-post-login.html

If I create a NEW USER on checkout then the checkout is normal and works fine.

If a previous user logs in on checkout (or if they are already logged in) then they cannot checkout.
Am seeing different types of bugs on checkout:

• User cannot complete final step on checkout, it will just keep on showing NEXT
• or User will be logged out when they press next in the checkout steps (or if they go to a previous step)
• or User will get a 404 error, going back to Home will show message "Cart is Empty" and they are also logged out

I have just taken two more orders by phone because they could not check out:

PayPal is selected as payment, on the final step they click NEXT to pay, but the system just loops them back to that same screen. It does not allow them to go and pay.

Hi,

I had to click one the NEXT button 2 times through the final step when selecting Paypal, but this issue is actually coming from the Auto submit shipping and payment methods selection option that you'll have to set to YES through "Hikashop->System->Configuration->Checkout".