Hello!
This is my case.
When I add a variable product to the cart, the pop up message does not show up although the ajax function is enabled. The page loads but the cart seems to be empty. The user should refresh the page one more time in order to see the product in the cart. The same goes when the user removes the product from the cart. The product is being removed after the second refresh.
You can check it out here https://dantemen.com/shop/bottoms/cloverleaf-pants-grey/
The simple products work as expected.
Thank you!