When countermeasures are linked to an issue tracker (Jira/Azure DevOps etc), which system is used as the source of truth for the state of the countermeasure?

Once a countermeasure has been linked to an issue on an issue tracker, the issue is used as the single source of truth for the status of the countermeasure.  I.e. when the ticket is marked as closed, then the countermeasure status will change to Implemented.  But if the countermeasure state is changed to Implemented, then this will have no effect on the ticket.  In fact, the countermeasure state will be reverted back to Required at the next sync interval, because the source of truth is the ticket status, not the countermeasure state.