1) Thank you! Are all changed files in child?
2) There was an update of Woocommerce and Litespeed plugins yesterday. I will observe it to see if this fixed it on both sites.
3) I enabled the Popup notification, so you can add a product in cart and try to remove it from the popup. As logged in, I don’t show any error in the console. As visitor, I see an error, but it may not be related.