diff --git a/pkg/core/region.go b/pkg/core/region.go
index 6875844b7a63..2ac323a12722 100644
--- a/pkg/core/region.go
+++ b/pkg/core/region.go
@@ -1339,8 +1339,8 @@ func (r *RegionsInfo) GetStoreWriteRate(storeID uint64) (bytesRate, keysRate flo
 
 // GetClusterNotFromStorageRegionsCnt gets the total count of regions that not loaded from storage anymore
 func (r *RegionsInfo) GetClusterNotFromStorageRegionsCnt() int {
-	r.st.RLock()
-	defer r.st.RUnlock()
+	r.t.RLock()
+	defer r.t.RUnlock()
 	return r.tree.notFromStorageRegionsCnt
 }
 
diff --git a/pkg/mcs/scheduling/server/cluster.go b/pkg/mcs/scheduling/server/cluster.go
index 09ae4ede5281..0c4e781e7471 100644
--- a/pkg/mcs/scheduling/server/cluster.go
+++ b/pkg/mcs/scheduling/server/cluster.go
@@ -206,7 +206,7 @@ func (c *Cluster) AllocID() (uint64, error) {
 	defer cancel()
 	resp, err := client.AllocID(ctx, &pdpb.AllocIDRequest{Header: &pdpb.RequestHeader{ClusterId: c.clusterID}})
 	if err != nil {
-		c.checkMembershipCh <- struct{}{}
+		c.triggerMembershipCheck()
 		return 0, err
 	}
 	return resp.GetId(), nil
@@ -215,12 +215,19 @@ func (c *Cluster) AllocID() (uint64, error) {
 func (c *Cluster) getAPIServerLeaderClient() (pdpb.PDClient, error) {
 	cli := c.apiServerLeader.Load()
 	if cli == nil {
-		c.checkMembershipCh <- struct{}{}
+		c.triggerMembershipCheck()
 		return nil, errors.New("API server leader is not found")
 	}
 	return cli.(pdpb.PDClient), nil
 }
 
+func (c *Cluster) triggerMembershipCheck() {
+	select {
+	case c.checkMembershipCh <- struct{}{}:
+	default: // avoid blocking
+	}
+}
+
 // SwitchAPIServerLeader switches the API server leader.
 func (c *Cluster) SwitchAPIServerLeader(new pdpb.PDClient) bool {
 	old := c.apiServerLeader.Load()