Q:

password invalid for customer created during checkout

I'm on a CE 1.9.3.1 with SUPEE 9652.
The password sent in the new account confirmation is blank. 
Moreover, if the customer attempts to login, the error message "Invalid login or password" is displayed.
I tried what's suggested here: customer's password not displayed in email templates magento 1.9.1.0
The modification of AccountController.php didn’t helped.
However, commenting 
$this->setData('password', null); 

in Mage\Customer\Model\Customer.php
solved half of the problem, as customer created with the "register" form receive the password and can login, but not the one registered during checkout.
The "check out created customer" lands in “My account” after the purchase but can't log again once logged-off (until he sets a new password with forgot password button). 
I thought it was relative to my theme, so I deleted all files in: /app/design/forontend/my_theme_package/my_theme_name/template But I'm still facing the same issue. 
I think that the password set during checkout is somehow wrongly stored.
Any suggestions?

A:

Got it, it was a strange issue ans I don't know where the error's coming from... The answer's here: 
https://stackoverflow.com/a/42474835/7553582

