Hello,

I have checked the notices on the mobile view on the checkout page. The height of the YITH reward message is greater than the YITH cart message notice that’s why it’s not displayed in one another.

You can try adding the following Custom CSS in the Custom CSS for Mobile area under Theme Settings >> Custom CSS.

#yith-par-message-reward-cart {
z-index: 1111;
}

This will make the Reward error to show before the cart message error.

Best Regards.