Hello, I came across this for a prestashop customer of mine and since I use OLS server, I checked out the LSCache plugin (https://www.litespeedtech.com/products/cache-plugins/prestashop-acceleration) and they state this at their FAQ:
Does LiteSpeed Cache for PrestaShop work with OpenLiteSpeed?
No, OpenLiteSpeed does not support ESI, and ESI is essential to the efficient caching of a PrestaShop store.
So, I guess it's only actually usable with LiteSpeed Enterprise?