In the Portfolio plan, we get to see the issues with status"Done" and Resolution "Done", But the ones with Status "Done" and Resolution - unresolved (since there is no post function set and there is no way to update that field) are not appearing in the plan.

Though the status is Done under different Jira Projects, in one of the Project where the resolution is "Unresolved", those entries only don't appear in Plan. The other Done-Done issues are appearing in the Portfolio plan.