Plugin Woocommerce problem.

Hello, everything is up-to-date and this is happening recently in the latest versions.

When not logged user is adding something to its cart and then goes to the cart the product disappears.

Or for example he/she adds something to the cart, then you can see 1 in the cart, let say we go to the blog (the 1 is still there) then comeback to the homepage and the cart is already empty.

When i stopped the plugin, everything seems to be okay.

What can i do in order to fix the problem and use the plugin, because i saw it is woocommerce compatible.

https://wordpress.org/plugins/wp-fastest-cache/