HR Help Desk Milestones not Completing

Summary:

Milestones for First Response and Resolution are set up, yet they are not automatically completing based on rules set up.

Content (please ensure you mask any confidential information):

SR is assigned to a resource; the resource responds, but First Response metric is showing as In Progress; they can manually mark it complete if the option is allowed, but we want it to automatically complete (to not give the option to manually complete).

First Response marked to complete when “User Sends Response”; is this the user that submitted the SR or the Agent responding? We have tested with both users responding with no result. We also tried selecting “Any Response Sent” for metric completion attribute and metric will still not automatically mark as complete.