Spectrum Policy blocking the ability to change an attribute value
When a model is a member of a Global Collection (GC) with a Policy attached, users will not be able to change the value of attributes set by the Policy.
This is functioning as designed.
If the model is a member of a GC it should not be a member of, you will need to either manually remove the model from the GC if it was manually added or modify the earch criteria of the GC so the model will not be meat the search criteria and be removed from the GC.
After the model is removed from the GC, you will be able to modify the attributes manually.
Please reference the "Policy Manager" section of the documentation for more information.