diff --git a/pkg/services/anonymous/anonimpl/anonstore/database.go b/pkg/services/anonymous/anonimpl/anonstore/database.go
index 0db2906709f..688409a0ab2 100644
--- a/pkg/services/anonymous/anonimpl/anonstore/database.go
+++ b/pkg/services/anonymous/anonimpl/anonstore/database.go
@@ -145,11 +145,17 @@ func (s *AnonDBStore) CreateOrUpdateDevice(ctx context.Context, device *Device)
 		}
 	}
 
+	// If CreatedAt time is not set (i.e. it's zero), and we end up creating the device, use current time as creation time.
+	// Spanner converts zero time to NULL, but CreatedAt is not nullable, so this helps to fix that problem too.
+	created := device.CreatedAt
+	if created.IsZero() {
+		created = time.Now()
+	}
 	if s.sqlStore.GetDBType() == migrator.Spanner {
-		return s.insertIntoSpanner(ctx, device)
+		return s.insertIntoSpanner(ctx, device, created)
 	}
 
-	args := []any{device.DeviceID, device.ClientIP, device.UserAgent, device.CreatedAt.UTC(), device.UpdatedAt.UTC()}
+	args := []any{device.DeviceID, device.ClientIP, device.UserAgent, created.UTC(), device.UpdatedAt.UTC()}
 	switch s.sqlStore.GetDBType() {
 	case migrator.Postgres:
 		query = `INSERT INTO anon_device (device_id, client_ip, user_agent, created_at, updated_at)
@@ -188,7 +194,7 @@ func (s *AnonDBStore) CreateOrUpdateDevice(ctx context.Context, device *Device)
 
 // In Spanner INSERT OR UPDATE only works when conflict is on primary key. However here we expect conflict on non-PK
 // column "device_id", so we need to use a transaction instead.
-func (s *AnonDBStore) insertIntoSpanner(ctx context.Context, dev *Device) error {
+func (s *AnonDBStore) insertIntoSpanner(ctx context.Context, dev *Device, created time.Time) error {
 	return s.sqlStore.WithTransactionalDbSession(ctx, func(dbSession *sqlstore.DBSession) error {
 		prev := &Device{DeviceID: dev.DeviceID}
 		ok, err := dbSession.Table(tableName).Get(prev)
@@ -196,7 +202,11 @@ func (s *AnonDBStore) insertIntoSpanner(ctx context.Context, dev *Device) error
 			return err
 		}
 		if !ok {
-			_, err = dbSession.Table(tableName).Insert(dev)
+			// Don't call Insert(dev) directly, because successful Insert modifies dev.DeviceID,
+			// but we don't do the same for other databases. That's why we create a copy.
+			devCopy := *dev
+			devCopy.CreatedAt = created
+			_, err = dbSession.Table(tableName).Insert(devCopy)
 			return err
 		}