I have created a lookup field as a site column in my root site. The field also brings several additional columns showing information from the list. It is used in a root site content type.
I have about 50 document libraries that use this content type.
If I update the field to bring more fields from the list, this doesn't get updated in the document libraries.
I know this is 'standard' behaviour, because content types in libraries are 'copies' of the original one, but I am trying to overcome this and update all my content types in the respective libraries.