Preload not preloading customposttypes

Hello, and congrats on your awesome plugin!
While I’ve been using this plugin for a client of mine, I noticed, that the preload cache feature, is not creating cache for a few instances.
The one which I am most troubled with is customposttypes (in this case, my site’s products.)
I have already checked the corresponding options in your preload cache feature.

Could you please tell me what the probable cause is for this?
(https://ibb.co/ZB3kjDh)

The page I need help with: [log in to see the link]