Magento 2: discount coupon not working ONLY on checkout page

I have Magento 2.3.3 and I noticed that the discount code is not working on the checkout page.
The weird thing is that, it is working on the cart page, but on the checkout it just doesn’t do nothing.

On top of that, the buttons don’t even have the text. In order to click on the right button, I had to inspect the element in order to see which one was the Cancel and which was the Apply.

Here is a screenshot

How can I fix it? Any suggestions?

Thanks!