Previously when a learner was reassigned (obliged to retake) a learning path, separate notifications were sent for every included course. Now the learner will receive notifications for the learning path as a whole, instead.
That said, you must be sure to have enabled the You have been assigned to retake a course and You have been assigned to retake a learning path notifications.
In the left navigation, make sure you are in the Academy Workspace.
In the Academy Workspace, navigate to Notifications, and then select Academy.
Here, select Courses & learning paths as a filter under the Training section.