感谢各位相助的大佬！
反馈一下：设置本地镜像，且关闭外网连接后，修改tikv参数重新加载无报错。
经测试：多机标准部署V6.1.0 和单机部署V8.5.1 均以解决。
日志如下：
[root@tidbcluster ~]# tiup cluster reload tidb-test
Will reload the cluster tidb-test with restart policy is true, nodes: , roles: .
Do you want to continue? [y/N]:(default=N) y
+ [ Serial ] - SSHKeySet: privateKey=/root/.tiup/storage/cluster/clusters/tidb-test/ssh/id_rsa, publicKey=/root/.tiup/storage/cluster/clusters/tidb-test/ssh/id_rsa.pub
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [Parallel] - UserSSH: user=tidb, host=192.168.169.41
+ [ Serial ] - UpdateTopology: cluster=tidb-test
+ Refresh instance configs
- Generate config pd -> 192.168.169.41:2379 ... Done
- Generate config tikv -> 192.168.169.41:20160 ... Done
- Generate config tikv -> 192.168.169.41:20161 ... Done
- Generate config tikv -> 192.168.169.41:20162 ... Done
- Generate config tidb -> 192.168.169.41:4000 ... Done
- Generate config tiflash -> 192.168.169.41:9000 ... Done
- Generate config prometheus -> 192.168.169.41:9090 ... Done
- Generate config grafana -> 192.168.169.41:3000 ... Done
+ Refresh monitor configs
- Generate config node_exporter -> 192.168.169.41 ... Done
- Generate config blackbox_exporter -> 192.168.169.41 ... Done
+ [ Serial ] - Upgrade Cluster
Upgrading component tiflash
Restarting instance 192.168.169.41:9000
Restart instance 192.168.169.41:9000 success
Upgrading component pd
Restarting instance 192.168.169.41:2379
Restart instance 192.168.169.41:2379 success
Upgrading component tikv
Evicting 2 leaders from store 192.168.169.41:20160...
Still waiting for 2 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Still waiting for 1 store leaders to transfer...
Restarting instance 192.168.169.41:20160
Restart instance 192.168.169.41:20160 success
Evicting 4 leaders from store 192.168.169.41:20161...
Still waiting for 4 store leaders to transfer...
Restarting instance 192.168.169.41:20161
Restart instance 192.168.169.41:20161 success
Evicting 5 leaders from store 192.168.169.41:20162...
Still waiting for 5 store leaders to transfer...
Still waiting for 5 store leaders to transfer...
Restarting instance 192.168.169.41:20162
Restart instance 192.168.169.41:20162 success
Upgrading component tidb
Restarting instance 192.168.169.41:4000
Restart instance 192.168.169.41:4000 success
Upgrading component prometheus
Restarting instance 192.168.169.41:9090
Restart instance 192.168.169.41:9090 success
Upgrading component grafana
Restarting instance 192.168.169.41:3000
Restart instance 192.168.169.41:3000 success
Stopping component node_exporter
Stopping instance 192.168.169.41
Stop 192.168.169.41 success
Stopping component blackbox_exporter
Stopping instance 192.168.169.41
Stop 192.168.169.41 success
Starting component node_exporter
Starting instance 192.168.169.41
Start 192.168.169.41 success
Starting component blackbox_exporter
Starting instance 192.168.169.41
Start 192.168.169.41 success
Reloaded cluster `tidb-test` successfully