Variants based on Manufacturers?

Hi all,

I am trying to set up an Item template, and be able to set up variants based on manufacturers model numbers. However I do not seem to have the option to set “Variants Based On” as “Manufacturers”, as described here:
https://erpnext.org/docs/user/manual/en/stock/item/item-variants

I have added the Manufacturer to the Item Supplier Details.

ERPNext: v10.1.18 (master)
Frappe Framework: v10.1.16 (master)

Thanks

When you’re creating a new item (template), create it in full page

Scroll down to Variants section and check Has Variants. You will get a drop down to select based on Manufacturers.

In the Item List, the Item has a Status of Enabled, other items with variants have a Status as Template.

When click on it to edit: ‘This Item is a Template and cannot be used in transactions’ is displayed

When Has Variants checkbox is clicked , the Variant Based On box is not a dropdown only Item Attribute.

I had originally clicked on the Has Variants checkbox and added a attribute , I later deleted the attribute and refreshed and reloaded , but the only option at that point was variant based on Item Attribute,

I have since deleted the template, and recreated - and the dropdown has both options. I chose Manufacturer following that, it is not possible to change it , even if Has Variants is unchecked, and the template is saved and the cache cleared.

I am not sure if this is as it should be or is a gift of inheritance, so to speak ( an immutable one at that! )