issue with tax class

Hello

I am unable to set up tax class on specific products
I will share images to better understand my issue
1- this is the set up on the tax page
https://ibb.co/FJxmNt1

2- set up classes
standered is set up this way since we have vendors and not all want to have vat on their products
https://ibb.co/jhGNH0N

website tax set up this way so a vendor can choose if they want to include a tax to their products or not
https://ibb.co/sQJh75B

The issue is when i go to a product and tried to change the class from standard to classA it does not, i hit update and check the product again and it is still the class as standard

why is this problem is there something wrong ? i have disabled the plugins but still same

The page I need help with: [log in to see the link]