Magento2 Custom Searchable attributes

As per instructions found at Algolia we’ve tried to set a list of Indexable attributes to sent from Magento 2.1.7 to Algolia. These configured attributes are being sent to and indexed by Algolia.
However, some default attributes like url for product or images are not being sent to or indexed by Algolia.
These are also not in the list to be picked.

Any idea, if we need to change something elsewhere?

I have also found instructions for Magento1.
These specific message is not mentioned at the Magento2 instructions.

"There are 11 attributes that the extension indexes regardless of what is specified in the table above. "
Those attributes are:
name Product’s name
url URL address of product in store
visibility_search If the product should be visible in search
visibility_catalog If the product should be visible in catalog
categories Tree of categories where the product belongs
categories_without_path Categories where the product belongs without it’s tree path
thumbnail_url URL of thumbnail image of the product
image_url URL of image of the product
in_stock If the product is on stock
price Price of the product
type_id Type of the product (simple, configurable, bundled, …)

Hello @mark.banis,

I just checked and url and image_url attributes should be always indexed.
Would you mind sharing with me your APPLICATION ID? Feel free to send it to support+magento@algolia.com and I’ll investigate further.

Thanks a lot!