Adding metadata to a file saved as a PDF/A 2b

A network scanner I use saves all PDF files as PDF/A  (2b I beleive because they are searchable).  As per standard many document modifcations are disabled including metadata.  I do not have administraiton privileges to modify the scanner settings and all the security settings under the Document properties are greyed-out as expected

I saved the scanned file to a other versions such as standard, reduced or optimized as a workaround but its remains as a PDF/A.

Am I stuck with a file to which I cannot add metadata?