diff --git a/channeldb/invoice_test.go b/channeldb/invoice_test.go
index ec54353d..fc61736a 100644
--- a/channeldb/invoice_test.go
+++ b/channeldb/invoice_test.go
@@ -1294,9 +1294,9 @@ func TestHTLCSet(t *testing.T) {
 	expSet2 := make(map[CircuitKey]*InvoiceHTLC)
 
 	checkHTLCSets := func() {
-		require.Equal(t, expSetNil, inv.HTLCSet(nil))
-		require.Equal(t, expSet1, inv.HTLCSet(setID1))
-		require.Equal(t, expSet2, inv.HTLCSet(setID2))
+		require.Equal(t, expSetNil, inv.HTLCSet(nil, HtlcStateAccepted))
+		require.Equal(t, expSet1, inv.HTLCSet(setID1, HtlcStateAccepted))
+		require.Equal(t, expSet2, inv.HTLCSet(setID2, HtlcStateAccepted))
 	}
 
 	// All HTLC sets should be empty initially.
diff --git a/channeldb/invoices.go b/channeldb/invoices.go
index 146e8d88..292a972e 100644
--- a/channeldb/invoices.go
+++ b/channeldb/invoices.go
@@ -471,17 +471,16 @@ type Invoice struct {
 	HodlInvoice bool
 }
 
-// HTLCSet returns the set of accepted HTLCs belonging to an invoice. Passing a
-// nil setID will return all accepted HTLCs in the case of legacy or MPP, and no
-// HTLCs in the case of AMP.  Otherwise, the returned set will be filtered by
-// the populated setID which is used to retrieve AMP HTLC sets.
-func (i *Invoice) HTLCSet(setID *[32]byte) map[CircuitKey]*InvoiceHTLC {
+// HTLCSet returns the set of HTLCs belonging to setID and in the provided
+// state. Passing a nil setID will return all HTLCs in the provided state in the
+// case of legacy or MPP, and no HTLCs in the case of AMP.  Otherwise, the
+// returned set will be filtered by the populated setID which is used to
+// retrieve AMP HTLC sets.
+func (i *Invoice) HTLCSet(setID *[32]byte, state HtlcState) map[CircuitKey]*InvoiceHTLC {
 	htlcSet := make(map[CircuitKey]*InvoiceHTLC)
 	for key, htlc := range i.Htlcs {
-		// Only consider accepted mpp htlcs. It is possible that there
-		// are htlcs registered in the invoice database that previously
-		// timed out and are in the canceled state now.
-		if htlc.State != HtlcStateAccepted {
+		// Only add HTLCs that are in the requested HtlcState.
+		if htlc.State != state {
 			continue
 		}
 
@@ -2039,7 +2038,7 @@ func updateInvoiceState(invoice *Invoice, hash *lntypes.Hash,
 
 		// Sanity check that the user isn't trying to settle or accept a
 		// non-existent HTLC set.
-		if len(invoice.HTLCSet(update.SetID)) == 0 {
+		if len(invoice.HTLCSet(update.SetID, HtlcStateAccepted)) == 0 {
 			return ErrEmptyHTLCSet
 		}
 
@@ -2329,8 +2328,8 @@ func (d *DB) DeleteInvoice(invoicesToDelete []InvoiceDeleteRef) error {
 			// invoice key.
 			key := invoiceAddIndex.Get(addIndexKey[:])
 			if !bytes.Equal(key, invoiceKey) {
-				return fmt.Errorf("unknown invoice in " +
-					"add index")
+				return fmt.Errorf("unknown invoice " +
+					"in add index")
 			}
 
 			// Remove from the add index.
diff --git a/invoices/update.go b/invoices/update.go
index e10b92c6..b41bd1a5 100644
--- a/invoices/update.go
+++ b/invoices/update.go
@@ -168,7 +168,7 @@ func updateMpp(ctx *invoiceUpdateCtx,
 		return nil, ctx.failRes(ResultHtlcSetTotalTooLow), nil
 	}
 
-	htlcSet := inv.HTLCSet(setID)
+	htlcSet := inv.HTLCSet(setID, channeldb.HtlcStateAccepted)
 
 	// Check whether total amt matches other htlcs in the set.
 	var newSetTotal lnwire.MilliSatoshi
@@ -373,7 +373,7 @@ func updateLegacy(ctx *invoiceUpdateCtx,
 	// Don't allow settling the invoice with an old style
 	// htlc if we are already in the process of gathering an
 	// mpp set.
-	for _, htlc := range inv.HTLCSet(nil) {
+	for _, htlc := range inv.HTLCSet(nil, channeldb.HtlcStateAccepted) {
 		if htlc.MppTotalAmt > 0 {
 			return nil, ctx.failRes(ResultMppInProgress), nil
 		}