diff --git a/errors.toml b/errors.toml
index b6123058310..a318fc32492 100644
--- a/errors.toml
+++ b/errors.toml
@@ -16,6 +16,11 @@ error = '''
 redirect failed
 '''
 
+["PD:apiutil:ErrRedirectToNotLeader"]
+error = '''
+redirect to not leader
+'''
+
 ["PD:autoscaling:ErrEmptyMetricsResponse"]
 error = '''
 metrics response from Prometheus is empty
diff --git a/pkg/errs/errno.go b/pkg/errs/errno.go
index b8a882cd187..a4320238374 100644
--- a/pkg/errs/errno.go
+++ b/pkg/errs/errno.go
@@ -197,6 +197,8 @@ var (
 var (
 	ErrRedirect       = errors.Normalize("redirect failed", errors.RFCCodeText("PD:apiutil:ErrRedirect"))
 	ErrOptionNotExist = errors.Normalize("the option %s does not exist", errors.RFCCodeText("PD:apiutil:ErrOptionNotExist"))
+	// ErrRedirectToNotLeader is the error message for redirect to not leader.
+	ErrRedirectToNotLeader = errors.Normalize("redirect to not leader", errors.RFCCodeText("PD:apiutil:ErrRedirectToNotLeader"))
 )
 
 // grpcutil errors
diff --git a/pkg/utils/apiutil/apiutil.go b/pkg/utils/apiutil/apiutil.go
index 8928688fed9..164b3c0783d 100644
--- a/pkg/utils/apiutil/apiutil.go
+++ b/pkg/utils/apiutil/apiutil.go
@@ -61,11 +61,6 @@ const (
 	// ForwardToMicroServiceHeader is used to mark the request is forwarded to micro service.
 	ForwardToMicroServiceHeader = "Forward-To-Micro-Service"
 
-	// ErrRedirectFailed is the error message for redirect failed.
-	ErrRedirectFailed = "redirect failed"
-	// ErrRedirectToNotLeader is the error message for redirect to not leader.
-	ErrRedirectToNotLeader = "redirect to not leader"
-
 	chunkSize = 4096
 )
 
@@ -459,7 +454,7 @@ func (p *customReverseProxies) ServeHTTP(w http.ResponseWriter, r *http.Request)
 		}
 		return
 	}
-	http.Error(w, ErrRedirectFailed, http.StatusInternalServerError)
+	http.Error(w, errs.ErrRedirect.FastGenByArgs().Error(), http.StatusInternalServerError)
 }
 
 // copyHeader duplicates the HTTP headers from the source `src` to the destination `dst`.
diff --git a/pkg/utils/apiutil/serverapi/middleware.go b/pkg/utils/apiutil/serverapi/middleware.go
index 1494dde27b8..26b36a88ca8 100644
--- a/pkg/utils/apiutil/serverapi/middleware.go
+++ b/pkg/utils/apiutil/serverapi/middleware.go
@@ -162,7 +162,13 @@ func (h *redirector) matchMicroServiceRedirectRules(r *http.Request) (bool, stri
 func (h *redirector) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
 	redirectToMicroService, targetAddr := h.matchMicroServiceRedirectRules(r)
 	allowFollowerHandle := len(r.Header.Get(apiutil.PDAllowFollowerHandleHeader)) > 0
-	if !h.s.IsClosed() && (allowFollowerHandle || h.s.GetMember().IsLeader()) && !redirectToMicroService {
+
+	if h.s.IsClosed() {
+		http.Error(w, errs.ErrServerNotStarted.FastGenByArgs().Error(), http.StatusInternalServerError)
+		return
+	}
+
+	if (allowFollowerHandle || h.s.GetMember().IsLeader()) && !redirectToMicroService {
 		next(w, r)
 		return
 	}
@@ -170,7 +176,7 @@ func (h *redirector) ServeHTTP(w http.ResponseWriter, r *http.Request, next http
 	// Prevent more than one redirection.
 	if name := r.Header.Get(apiutil.PDRedirectorHeader); len(name) != 0 {
 		log.Error("redirect but server is not leader", zap.String("from", name), zap.String("server", h.s.Name()), errs.ZapError(errs.ErrRedirect))
-		http.Error(w, apiutil.ErrRedirectToNotLeader, http.StatusInternalServerError)
+		http.Error(w, errs.ErrRedirectToNotLeader.FastGenByArgs().Error(), http.StatusInternalServerError)
 		return
 	}
 
@@ -189,7 +195,7 @@ func (h *redirector) ServeHTTP(w http.ResponseWriter, r *http.Request, next http
 	var clientUrls []string
 	if redirectToMicroService {
 		if len(targetAddr) == 0 {
-			http.Error(w, apiutil.ErrRedirectFailed, http.StatusInternalServerError)
+			http.Error(w, errs.ErrRedirect.FastGenByArgs().Error(), http.StatusInternalServerError)
 			return
 		}
 		clientUrls = append(clientUrls, targetAddr)
diff --git a/scripts/ci-subtask.sh b/scripts/ci-subtask.sh
index a2e396088d6..dd29895327b 100755
--- a/scripts/ci-subtask.sh
+++ b/scripts/ci-subtask.sh
@@ -29,11 +29,22 @@ else
     weight() {
         [[ $1 == "github.com/tikv/pd/server/api" ]] && return 30
         [[ $1 == "github.com/tikv/pd/pkg/schedule" ]] && return 30
-        [[ $1 == "pd/tests/server/api" ]] && return 30
+        [[ $1 == "github.com/tikv/pd/pkg/core" ]] && return 30
+        [[ $1 == "github.com/tikv/pd/tests/server/api" ]] && return 30
         [[ $1 =~ "pd/tests" ]] && return 5
         return 1
     }
 
+    # Create an associative array to store the weight of each task.
+    declare -A task_weights
+    for t in ${tasks[@]}; do
+        weight $t
+        task_weights[$t]=$?
+    done
+
+    # Sort tasks by weight in descending order.
+    tasks=($(printf "%s\n" "${tasks[@]}" | sort -rn))
+
     scores=($(seq "$1" | xargs -I{} echo 0))
 
     res=()
@@ -42,8 +53,7 @@ else
         for i in ${!scores[@]}; do
             [[ ${scores[i]} -lt ${scores[$min_i]} ]] && min_i=$i
         done
-        weight $t
-        scores[$min_i]=$((${scores[$min_i]} + $?))
+        scores[$min_i]=$((${scores[$min_i]} + ${task_weights[$t]}))
         [[ $(($min_i + 1)) -eq $2 ]] && res+=($t)
     done
     printf "%s " "${res[@]}"
diff --git a/server/apiv2/middlewares/redirector.go b/server/apiv2/middlewares/redirector.go
index 285f096e823..37c06de1585 100644
--- a/server/apiv2/middlewares/redirector.go
+++ b/server/apiv2/middlewares/redirector.go
@@ -30,9 +30,13 @@ import (
 func Redirector() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		svr := c.MustGet(ServerContextKey).(*server.Server)
+
+		if svr.IsClosed() {
+			c.AbortWithStatusJSON(http.StatusInternalServerError, errs.ErrServerNotStarted.FastGenByArgs().Error())
+			return
+		}
 		allowFollowerHandle := len(c.Request.Header.Get(apiutil.PDAllowFollowerHandleHeader)) > 0
-		isLeader := svr.GetMember().IsLeader()
-		if !svr.IsClosed() && (allowFollowerHandle || isLeader) {
+		if allowFollowerHandle || svr.GetMember().IsLeader() {
 			c.Next()
 			return
 		}
@@ -46,12 +50,11 @@ func Redirector() gin.HandlerFunc {
 
 		c.Request.Header.Set(apiutil.PDRedirectorHeader, svr.Name())
 
-		leader := svr.GetMember().GetLeader()
-		if leader == nil {
+		if svr.GetMember().GetLeader() == nil {
 			c.AbortWithStatusJSON(http.StatusServiceUnavailable, errs.ErrLeaderNil.FastGenByArgs().Error())
 			return
 		}
-		clientUrls := leader.GetClientUrls()
+		clientUrls := svr.GetMember().GetLeader().GetClientUrls()
 		urls := make([]url.URL, 0, len(clientUrls))
 		for _, item := range clientUrls {
 			u, err := url.Parse(item)
diff --git a/tests/integrations/mcs/keyspace/tso_keyspace_group_test.go b/tests/integrations/mcs/keyspace/tso_keyspace_group_test.go
index 1415acc46d1..7dcce498d56 100644
--- a/tests/integrations/mcs/keyspace/tso_keyspace_group_test.go
+++ b/tests/integrations/mcs/keyspace/tso_keyspace_group_test.go
@@ -301,7 +301,10 @@ func (suite *keyspaceGroupTestSuite) TestDefaultKeyspaceGroup() {
 		return code == http.StatusOK && kg != nil
 	}, testutil.WithWaitFor(time.Second*1))
 	suite.Equal(utils.DefaultKeyspaceGroupID, kg.ID)
-	suite.Len(kg.Members, utils.DefaultKeyspaceGroupReplicaCount)
+	// the allocNodesToAllKeyspaceGroups loop will run every 100ms.
+	testutil.Eventually(suite.Require(), func() bool {
+		return len(kg.Members) == utils.DefaultKeyspaceGroupReplicaCount
+	})
 	for _, member := range kg.Members {
 		suite.Contains(nodes, member.Address)
 	}