How to get the "Time with Assignee" time until the issue was resolved using the Reports and Timesheets for Jira app
By default, the field “Time with Assignee” will consider the time an issue has spent with a particular user, even after the issue is set as Resolved.
To only consider the time until an issue has been set as “Resolved”, the Calculated Field can be built as below:
The above Calculated Field evaluates the following:
If the displayed user is the current assignee (Current Assignee? field).
If the “Resolution” of the issue is not empty.
If both statements above are true, the calculated field will be set to the business days between the “Resolved” and the “Assignee start” date. Otherwise, the calculated field will show the “Time with assignee (business days)” as a result.
Reference: 11. Time with Assignee Report - 6.5.7