The grader is confused because you have 2 Meeting ID fields - one is correctly connecting Julia to the Mtg-01 meeting record but the other is blank. You need to go into your Meeting Attendance object and delete the extra Meeting ID that is blank and unused. Keep the one that is the Lookup field connected to Meeting but delete the other one and then regrade and refresh and it should be fixed.
The grader is confused because you have 2 Meeting ID fields - one is correctly connecting Julia to the Mtg-01 meeting record but the other is blank. You need to go into your Meeting Attendance object and delete the extra Meeting ID that is blank and unused. Keep the one that is the Lookup field connected to Meeting but delete the other one and then regrade and refresh and it should be fixed.