Why do incomplete performance review reminders go to managers of terminated employees?

Summary:

As part of our (mid-year) performance review process, we turned on a reminder notification:

Performance > Talent Notifications > Performance Management > Standard Alert Due Date has been reached for a task

As expected, users and managers who did not complete their potion of the Performance Document (review) received the reminder. However, managers of terminated users also received reminders. For example, an active employee received the Performance Document. They left the company shortly after — and before the review period closed — leaving an incomplete review.

Why are managers sent reminders for terminated employees? Is there any way to stop notifications to terminated users and their managers? And similarly, is there a way to stop notifications / reminders for Suspended employees (and managers of Suspended employees)?