diff --git a/pkg/store/store_test.go b/pkg/store/store_test.go
index 845d9ac..c91ba49 100644
--- a/pkg/store/store_test.go
+++ b/pkg/store/store_test.go
@@ -227,6 +227,23 @@ func TestStore(t *testing.T) {
 		}
 	})
 
+	t.Run("IsSettled", func(t *testing.T) {
+		st, err := store.NewStore(db)
+		if err != nil {
+			t.Fatalf("Failed to create store: %s", err)
+		}
+
+		for _, settlement := range settlements {
+			settled, err := st.IsSettled(context.Background(), settlement.CommitmentIdx)
+			if err != nil {
+				t.Fatalf("Failed to check if settled: %s", err)
+			}
+			if !settled {
+				t.Fatalf("Expected settlement to be settled")
+			}
+		}
+	})
+
 	t.Run("SubscribeSettlements", func(t *testing.T) {
 		st, err := store.NewStore(db)
 		if err != nil {
diff --git a/pkg/updater/updater.go b/pkg/updater/updater.go
index 2683996..f64d5b9 100644
--- a/pkg/updater/updater.go
+++ b/pkg/updater/updater.go
@@ -9,6 +9,7 @@ import (
 	"math"
 	"math/big"
 	"strings"
+	"sync"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -63,6 +64,8 @@ type Updater struct {
 	evtMgr           events.EventManager
 	l1BlockCache     *lru.Cache[uint64, map[string]int]
 	l2BlockTimeCache *lru.Cache[uint64, uint64]
+	encryptedMu      sync.Mutex
+	openedCmtMu      sync.Mutex
 	metrics          *metrics
 }
 
@@ -124,6 +127,9 @@ func (u *Updater) subscribeEncryptedCommitments(ctx context.Context) error {
 	ev := events.NewEventHandler(
 		"EncryptedCommitmentStored",
 		func(update *preconf.PreconfcommitmentstoreEncryptedCommitmentStored) error {
+			u.encryptedMu.Lock()
+			defer u.encryptedMu.Unlock()
+
 			err := u.winnerRegister.AddEncryptedCommitment(
 				ctx,
 				update.CommitmentIndex[:],
@@ -164,6 +170,9 @@ func (u *Updater) subscribeOpenedCommitments(ctx context.Context) error {
 	ev := events.NewEventHandler(
 		"CommitmentStored",
 		func(update *preconf.PreconfcommitmentstoreCommitmentStored) error {
+			u.openedCmtMu.Lock()
+			defer u.openedCmtMu.Unlock()
+
 			alreadySettled, err := u.winnerRegister.IsSettled(ctx, update.CommitmentIndex[:])
 			if err != nil {
 				u.logger.Error(
@@ -176,7 +185,10 @@ func (u *Updater) subscribeOpenedCommitments(ctx context.Context) error {
 			if alreadySettled {
 				// both bidders and providers could open commitments, so this could
 				// be a duplicate event
-				u.logger.Info("duplicate open commitment event", "commitmentIdx", common.Bytes2Hex(update.CommitmentIndex[:]))
+				u.logger.Info(
+					"duplicate open commitment event",
+					"commitmentIdx", common.Bytes2Hex(update.CommitmentIndex[:]),
+				)
 				return nil
 			}