Approval when proposed LM is same as current LM

Summary:

Approval is sent to initiator when LM initiates Transfer and there is no change in supervisor hierarchy for the worker

Content (please ensure you mask any confidential information):

We have configured approval when a LM initiates transfer. The approval is sent to proposed Line Manager. But when the Line Manager is not changing, approval is sent to the same Line Manager who initiates the transfer. From BPM I have selected "Don't send multiple notifications for the same human task event" but still it does not work and sends approval to same person. Any suggestions on how to fix this so that if proposed LM is not changing, approval is not sent to the same person?