diff --git a/roomserver/internal/helpers/helpers_test.go b/roomserver/internal/helpers/helpers_test.go
new file mode 100644
index 000000000..aa5c30e44
--- /dev/null
+++ b/roomserver/internal/helpers/helpers_test.go
@@ -0,0 +1,56 @@
+package helpers
+
+import (
+	"context"
+	"testing"
+
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/stretchr/testify/assert"
+
+	"github.com/matrix-org/dendrite/setup/base"
+
+	"github.com/matrix-org/dendrite/test"
+	"github.com/matrix-org/dendrite/test/testrig"
+
+	"github.com/matrix-org/dendrite/roomserver/storage"
+)
+
+func mustCreateDatabase(t *testing.T, dbType test.DBType) (*base.BaseDendrite, storage.Database, func()) {
+	base, close := testrig.CreateBaseDendrite(t, dbType)
+	db, err := storage.Open(base, &base.Cfg.RoomServer.Database, base.Caches)
+	if err != nil {
+		t.Fatalf("failed to create Database: %v", err)
+	}
+	return base, db, close
+}
+
+func TestIsInvitePendingWithoutNID(t *testing.T) {
+
+	alice := test.NewUser(t)
+	bob := test.NewUser(t)
+	room := test.NewRoom(t, alice, test.RoomPreset(test.PresetPublicChat))
+	_ = bob
+	test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
+		_, db, close := mustCreateDatabase(t, dbType)
+		defer close()
+
+		// store all events
+		var authNIDs []types.EventNID
+		for _, x := range room.Events() {
+
+			evNID, _, _, _, _, err := db.StoreEvent(context.Background(), x.Event, authNIDs, false)
+			assert.NoError(t, err)
+			authNIDs = append(authNIDs, evNID)
+		}
+
+		// Alice should have no pending invites and should have a NID
+		pendingInvite, _, _, _, err := IsInvitePending(context.Background(), db, room.ID, alice.ID)
+		assert.NoError(t, err, "failed to get pending invites")
+		assert.False(t, pendingInvite, "unexpected pending invite")
+
+		// Bob should have no pending invites and receive a new NID
+		pendingInvite, _, _, _, err = IsInvitePending(context.Background(), db, room.ID, bob.ID)
+		assert.NoError(t, err, "failed to get pending invites")
+		assert.False(t, pendingInvite, "unexpected pending invite")
+	})
+}
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index 958787070..08e912a00 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -111,7 +111,7 @@ func (d *Database) eventStateKeyNIDs(
 		result[eventStateKey] = nid
 	}
 	// We received some nids, but are still missing some, work out which and create them
-	if len(eventStateKeys) < len(result) {
+	if len(eventStateKeys) > len(result) {
 		for _, eventStateKey := range eventStateKeys {
 			if _, ok := result[eventStateKey]; ok {
 				continue