Custimization fields are not saving the product custimization

[Eljaouhari]

Hello everyone, I hope you're having a great day.

I'm currently on prestashop 1.7 and I have already a non understandable amount of products on line.
The problem I'm struggling with is that after some css editing of the template I found out that my customization fields module is not saving the customization for products.

After reading the code of the customization form I find out that the normal behaviour is leading me to the product page after click on "save" but what happens is that I end up on the cart page and the customization is not saving.

I'm using the theme "pos oregon 4".

I'll be really grateful if someone can help me solve the problem.

Thanks in advance..

 

Can it be because of missing files ? or something I don't know about ?