I'm trying to use a radioactivity field as a sort by "Bestsellers" in my search created with search_api + search_api_db + search_api_sorts.

- i have a product display (node)
-- a commerce product reference field (unlimited values)
--- in the product (entity) referenced i have a radioactivity field (single value)

But the field is not displayed in the list of fields available to use as a sort option because, although the field is "single" valued, he is inheriting the "multiple" configuration of the product reference field and multiple valued fields are not sortable.

if i change the product reference field in the product display to a single value, the radioactivity field appears in the sorts list.

thank you!