New account created after payment but automatic account creation is set to no

Hi,

I am running a dev site (v1.5.1) and I am testing Paypal Express in sandbox mode. I created a sanbox paypal account to do the tests and after using it and completing a payment with the express checkout option I found out that a zencart client account had been created. I copy below my Paypal settings.

Any hints about what can be going on? I wasn't asked for a password for the new store account at any moment, so this is really messy.

Thanks a lot! :) I can't provide a link to my store because is not public yet, but I can provide it through DM.

Settings:

Express Checkout Shortcut Button
On

Set Order Status
por defecto

Set Unpaid Order Status
por defecto

Set Refund Order Status
por defecto

Express Checkout: Require Confirmed Address
No

Express Checkout: Select Cheapest Shipping Automatically
No

Express Checkout: Skip Payment Page
Yes

Express Checkout: Automatic Account Creation
No

Payment Action
Final Sale

Allow eCheck?
Instant Only

More info: when I use the same Paypal account to pay another order and then click on "my account" there is only the last order showing up. At the admin page, the client associated to that new account has also associated only the last order, even if the one before the last one still appears listed under "orders" assigned to the same email.

I am really confused...