Can employer request for I140 revoke by backdating it?

My I 140 with current employer has been approved on Feb 21st 2021. I have a job offer from another employer B who is filing for H1B transfer. After Aug 21st 2021(after 180 days of completion of I140 approval) , I am planning to inform my current employer A that I would be leaving them in 2 weeks from thereon after which I assume my current employer A would sent request for revoking my I 140 immediately.
Can they backdate the effective date for revoke request to hurt my chances and make it seem like it was sent within 180 days from approval? As it is a edge case , I am trying to be cautious and thinking of all possible scenarios that may impact me negatively.

They can’t back date the withdrawal of I-140.