There are some of user got issue with Woocommerce Booking that empty checkout cart when using WP Rocket. Please refer our document here for more detail about this case:
Cache mini cart
Exclude Based on Cookies
Pages can be excluded from the cache based on the presence of a cookie.
Go to WP Rocket → Advanced Rules and enter the following value in the Never Cache Cookies field add woocommerce_items_in_cart
Then, setting Never Cache URL(s) section, add these URL:
Please refer the photo attach