In order for a document to be shared to the OP Patient Portal, the privacy level (or visibility) must be set to Any Staff Member. If the document must no longer be shared, the Shared to Portal checkbox must be deselected prior to changing the privacy level of the document.
OP sets all defaults to share all information. Any individual decisions by Practice-users to restrict information sharing (access, use, or exchange) are the responsibility of the Practice in the implementation of its 21st Century Cures Act Information Blocking policies and procedures for its Practice and patients.