Scaling in TiKV blocked by `not found in cluster` error

Bug Report

What version of Kubernetes are you using?

What version of TiDB Operator are you using?

v1.3.2
What storage classes exist in the Kubernetes cluster and what are used for PD/TiKV pods?

What's the status of the TiDB cluster pods?

# k -n tidb60441 get pod
NAME                            READY   STATUS      RESTARTS   AGE
db-discovery-7b5b664f88-wkhgr   1/1     Running     0          3h48m
db-monitor-0                    3/3     Running     0          3h48m
db-pd-0                         1/1     Running     0          3h48m
db-tidb-0                       3/3     Running     0          107m
db-tidb-initializer-b29tn       0/1     Completed   0          3h48m
db-tikv-3                       1/1     Running     0          57m
db-tikv-4                       1/1     Running     0          57m
db-tikv-5                       1/1     Running     0          57m
db-tikv-6                       1/1     Running     0          34m
db-tikv-7                       1/1     Running     0          34m
db-tikv-8                       1/1     Running     0          34m

What did you do?

Scale out 3 new Pods and then scale in 3 Pods very soon
What did you expect to see?
The Pods are scaled in
What did you see instead?
The latest Pod tikv-8 cannot scale in