By default, CheckoutWC displays cart item data in a shortened format.
So for example, when purchasing a Red shirt in the Medium size, it will display like:
Shirt
Red / Medium
When using WooCommerce Deposits, this produces unusual output:
To fix this, head over to Settings > CheckoutWC > Cart Summary and change Cart Item Data Display to WooCommerce Default.
This will cause the cart item data to display properly: