Muse Spark 1.3 got stuck on the product page

Every step

1. 0:04StoreClicked “Aero Run 2 Light running shoes for everyday roa…”“I see featured products on the home page, so I will open the first product page.”
2. 0:08Product pageClicked “Choose a size”“I am on the Aero Run 2 product page and need to choose a size before adding to cart, so I'll open the size dropdown.”
3. 0:15Product pagePicked “42”“I see the size dropdown open with 42 in stock, so I'll select that size now.”
4. 0:29Product pagePicked “43”“I see the size dropdown open with 42 and 43 available, my last select failed, so I will try the other in-stock size.”
5. 0:44Product pageClicked “Add to cart”“The size dropdown is open showing 42 and 43 in stock but they have no IDs I can click. I'll try Add to cart to see what happens.”
6. 0:55Product pageClicked “Choose a size 40 – out of stock 41 – out of sto…”“The size dropdown is open showing 42 available but options have no separate ids, so I'll try clicking the dropdown control to select it.”