Resend when not needed

Imported from previous forum

Our system sends a sequence reset message in response to any resend request received. All orders in the resend gap are sent as new orders in case they are re-priced by the system. The new re-priced orders are not PossDup and are not PossResend either.

This should be according to spec:
"…the sender may not wish to retransmit the order given the potentisl for changed market conditions."

But, what if a counterparty resend requests even though it may have already processesed some of the messages it is requesting to be resent?

Is this resend request legal?