diff --git a/channeldb/payments.go b/channeldb/payments.go
index 0e2b865df..c3c093269 100644
--- a/channeldb/payments.go
+++ b/channeldb/payments.go
@@ -607,6 +607,15 @@ func serializeHop(w io.Writer, h *route.Hop) error {
 		records = append(records, h.MPP.Record())
 	}
 
+	// Final sanity check to absolutely rule out custom records that are not
+	// custom and write into the standard range.
+	if err := h.CustomRecords.Validate(); err != nil {
+		return err
+	}
+
+	// Convert custom records to tlv and add to the record list.
+	// MapToRecords sorts the list, so adding it here will keep the list
+	// canonical.
 	tlvRecords := tlv.MapToRecords(h.CustomRecords)
 	records = append(records, tlvRecords...)
 
diff --git a/channeldb/payments_test.go b/channeldb/payments_test.go
index 8eba5e5ac..16e952df4 100644
--- a/channeldb/payments_test.go
+++ b/channeldb/payments_test.go
@@ -28,8 +28,8 @@ var (
 		OutgoingTimeLock: 111,
 		AmtToForward:     555,
 		CustomRecords: record.CustomSet{
-			1: []byte{},
-			2: []byte{},
+			65536: []byte{},
+			80001: []byte{},
 		},
 		MPP: record.NewMPP(32, [32]byte{0x42}),
 	}