Hi Craig,
I believe you are referring to this fix,
TL-38107: prevented sending notifications to suspended users A change was made to the core centralised notification system to prevent all notifications being sent to users who are suspended or deleted or to all recipients when the subject of a notification is suspended or deleted.
It only mentioned about suspended users. Are you able to check if this fix apply to the manager of the suspended user? If not, could you please raise this bug in your issue tracker? Many thanks.
Best regards,
Allison