issue with multi products in my shop only on Mobile

I have a problem when I add the product for the first time to the basket, I can do that, but when I add any other product after that to the basket, I cannot, as it appears in the video, I can add product No. 1 to the basket, but No. 2, No. 3, or any product number else I can’t

the problem only on Mobile not Desktop

www.arrambooks.de