Products automatically deleted from the cart during checkout

[Grafichero]

Hi, I have a problem with Prestashop 1.7 Cart.

If you add an item to cart and perform user registration in the next step the cart is lost.

Steps to reproduce the behavior:

Add an item to the cart
And complete the checkout performing also new user registration
In the next step, the address registration, when you activate one field the cart is emptied.

Can you please check and suggest a solution?

Best regards.

[El Patron]

Enable debug mode and reproduce to see if error.  You can also use Chrome inspect console to see if error.