diff --git a/score.go b/score.go
index 20bf125..42dc439 100644
--- a/score.go
+++ b/score.go
@@ -144,7 +144,7 @@ type messageDeliveries struct {
 type deliveryRecord struct {
 	firstSeen time.Time
 	status    int
-	peers     map[peer.ID]time.Time
+	peers     map[peer.ID]struct{}
 }
 
 // delivery record status
@@ -375,10 +375,10 @@ func (ps *peerScore) DeliverMessage(msg *Message) {
 
 	drec := ps.deliveries.getRecord(ps.msgID(msg.Message))
 
-	// mark the message as valid and reward mesh peers that have forwarded it in time
+	// mark the message as valid and reward mesh peers that have already forwarded it to us
 	drec.status = delivery_valid
-	for p, t := range drec.peers {
-		ps.markDuplicateMessageDelivery(p, msg, drec.firstSeen, t)
+	for p := range drec.peers {
+		ps.markDuplicateMessageDelivery(p, msg, time.Time{})
 	}
 }
 
@@ -446,16 +446,14 @@ func (ps *peerScore) DuplicateMessage(msg *Message) {
 
 	switch drec.status {
 	case delivery_unknown:
-		// the message is being validated; track the peer delivery time and wait for
+		// the message is being validated; track the peer delivery and wait for
 		// the Deliver/Reject notification.
-		now := time.Now()
-		drec.peers[msg.ReceivedFrom] = now
+		drec.peers[msg.ReceivedFrom] = struct{}{}
 
 	case delivery_valid:
 		// mark the peer delivery time to only count a duplicate delivery once.
-		now := time.Now()
-		drec.peers[msg.ReceivedFrom] = now
-		ps.markDuplicateMessageDelivery(msg.ReceivedFrom, msg, drec.firstSeen, now)
+		drec.peers[msg.ReceivedFrom] = struct{}{}
+		ps.markDuplicateMessageDelivery(msg.ReceivedFrom, msg, drec.firstSeen)
 
 	case delivery_invalid:
 		// we no longer track delivery time
@@ -536,12 +534,18 @@ func (ps *peerScore) markFirstMessageDelivery(p peer.ID, msg *Message) {
 	}
 }
 
-func (ps *peerScore) markDuplicateMessageDelivery(p peer.ID, msg *Message, firstSeen, deliveryTime time.Time) {
+func (ps *peerScore) markDuplicateMessageDelivery(p peer.ID, msg *Message, firstSeen time.Time) {
+	var now time.Time
+
 	pstats, ok := ps.peerStats[p]
 	if !ok {
 		return
 	}
 
+	if !firstSeen.IsZero() {
+		now = time.Now()
+	}
+
 	for _, topic := range msg.GetTopicIDs() {
 		tstats, ok := pstats.getTopicStats(topic, ps.params)
 		if !ok {
@@ -552,8 +556,10 @@ func (ps *peerScore) markDuplicateMessageDelivery(p peer.ID, msg *Message, first
 			continue
 		}
 
-		// check against the mesh delivery window
-		if deliveryTime.After(firstSeen.Add(ps.params.Topics[topic].MeshMessageDeliveriesWindow)) {
+		// check against the mesh delivery window -- if the firstSeen time is passed as 0, then now
+		// will also be zero and the message was received before we finished validation and thus falls
+		// within the mesh delivery window.
+		if !now.IsZero() && now.After(firstSeen.Add(ps.params.Topics[topic].MeshMessageDeliveriesWindow)) {
 			continue
 		}