When an asset is shared from one workspace to another, only the original copy can be edited or otherwise modified, even if you have permissions for every workspace it appears in. If you attempt to alter the asset inside one of the folders it has been shared to, you will see a popup informing you that you don't have sufficient privileges to do so.
To edit the asset, make sure you are working with the original copy of that asset, located within the workspace where it was first created.