network/sync: Received notification that was refused earlier by SyncingEngine

[lexnv]

Reproduced on kusama validator. Confirmed at the moment for litep2p, libp2p pending investigation:

ERROR tokio-runtime-worker sync: received notification from 12D3KooWMb8BgRtEXdG2PGK5mve2nYX2uzAYJ6VhnX9i6hAod4mV who had been earlier refused by `SyncingEngine`

Version deployed: version 1.16.1-ca8beaed148

polkadot-sdk/substrate/client/network/sync/src/engine.rs

Lines 747 to 753 in 3906c57

	if !self.peers.contains_key(&peer) {
	log::error!(
	target: LOG_TARGET,
	"received notification from {peer} who had been earlier refused by `SyncingEngine`",
	);
	return;
	}

Grafana link: https://grafana.teleport.parity.io/goto/msBvOdnNg?orgId=1

cc @paritytech/sdk-node

[dmitry-markin]

This might be introduced by #5737, but let's wait for confirmation with libp2p backend.