Links between map elements indicate acknowledged problems even if the map is configured to display unacknowledged problems only

Steps to reproduce:

1. Create an item and a Trigger for this item.
2. Create a map under Monitoring => Maps , "Problem display" is set to all.
3. Add 2 trigger elements to the map (at least one of them should include the created trigger).
4. Add a link between these two elements and specify a link indicator that is based on the previously created trigger.
5. Set the previously created trigger into status "Problem".
6. Open the map and confirm that both the link and the label of the map element indicate that there's a problem.
7. Navigate to Monitoring => Problems and acknowledge the problem.
8. Navigate to Monitoring => Maps and open the Properties of the previously created map.
9. Change the value of "Problem display" parameter from "All" to "Unacknowledged only" and press "Update" button.
10. Open the previously created map.

Result: The color of the link between the two elements of the map still indicates that there's a problem even though the problem is acknowledged and the map is configured to display unacknowledged problems only.

Expected: The link between the map elements should not indicate an acknowledged problem if the map is configured to display unacknowledged problems only.