%asset_href% generating the same result as %asset_link%

I am trying to use the %asset_href% or %global_asset_href% in a Design to create a 'link rel="canonical"' tag.


I've also tried <MySource_PRINT id_name="global" var="asset_href" />



In each instance the "asset_href" generating the same result as if I'd use "asset_link" instead.



That is it is not generating the full path.



Am I missing something? (we are on v3.26.2)



Note I dont want to use "asset_url" (which works fine btw) as we have multiple URLs on the one site asset and I'm trying to tell Google the canonical one.



Also I've gone down this path as I couldn't work out how to apply a different robots.txt for the different URLs