You may see a message about a benefit delay on your benefit dashboard while the graph shows a delay. This happens when a project that is linked to the benefit has been delayed.
If you review the project dashboard, you'll notice the benefit has been linked to a delivery milestone, which means that the benefits start date is dependent on the milestone end date. A delayed milestone end date will delay the benefit.
How the benefit delay affects measures is described in Why should I link benefits to project milestones?