When you restrict update access to a Librarian Master file to read-only access you will need to use -EXTRACT instead of -SEL when accessing the member.
The -EXTRACT command does not require update authority to the master file. The -SEL(SELECT) command does require update authority to the master file.
When a -SEL is processed, even if no updates, it requires an update to the "module last accessed" date included as part of the Module Management Block.