How can absence notification be reverted back to seeded Notification title?

Summary:

When we changed absence notification title from the seeded to custom and reverted it back to original, It started displaying notification title as "HtTitle.Approvalof0TimeoffRequestfor1from2to3".

Content (please ensure you mask any confidential information):

Initially, we changed notification header from the BIP Task Configuration to a custom notification and then reverted it back to original notification header expression which is "/task:task/task:payload/task:NotificationTitleKey". Despite making changes to original seeded notification title the notification title on email shows like this "HtTitle.Approvalof0TimeoffRequestfor1from2to3".

Other steps performed as below:

I have also checked notification template for custom notification in "