AJAX Error on product page. When changing quantity and also when adding to cart

[Sorrors]

Hello,
Let's see if someone can help me with the problem I have,

The error occurs on the product page when I change the quantity or add to cart. It seems that the Prestashop AJAX is not able to recognize the current quantity of the product. It happens in all products. It only happens when the language extension is in the URL. If I leave Prestashop with only one language everything works fine, so the problem comes from something related to the language extension in the URL. When the url has something like .../en/... or .../es/... it always gives the error.

I did a clean install, so it's really unlikely that it's a third-party module that's causing the error.

 

 

 

Prestashop v8.1.3

Theme: Warehouse 4.6.4

PHP: 8.1