Unable to revoke a service entry sheet. Error "M7 021 Deficit of PU IR quantity 0.001 AU"

Scenario is this

1) Service purchase order created

2) SES created and accepted

3) Invoice posted

4)Credit Memo posted

5) Tried to Revoke SES

Noticing the below error "M7 021 Deficit of PU IR quantity 0.001 AU".

There is no deficit of PU IR quantity.

GR based Invoice verification is checked.

Can you help on this issue.

Regards

Pushpa