It is indeed removed, but the removed raft id is 9, now it is 12. Checking the status information of zero, 12 has indeed not been used.
"removed":[{"id":"3","groupId":1,"addr":"dgraph-alpha-2.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"1615991006","clusterInfoOnly":false,"forceGroupId":false},{"id":"4","groupId":1,"addr":"dgraph-alpha-2.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"0","clusterInfoOnly":false,"forceGroupId":false},{"id":"5","groupId":1,"addr":"dgraph-alpha-2.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"0","clusterInfoOnly":false,"forceGroupId":false},{"id":"1","groupId":0,"addr":"dgraph-zero-0.dgraph-zero.crm-test.svc.cluster.local:5080","leader":true,"amDead":false,"lastUpdate":"0","clusterInfoOnly":false,"forceGroupId":false},{"id":"1","groupId":1,"addr":"dgraph-alpha-0.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"1615990975","clusterInfoOnly":false,"forceGroupId":false},{"id":"7","groupId":1,"addr":"dgraph-alpha-0.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"1620716707","clusterInfoOnly":false,"forceGroupId":false},{"id":"9","groupId":2,"addr":"dgraph-alpha-4.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"1620719808","clusterInfoOnly":false,"forceGroupId":false},{"id":"11","groupId":2,"addr":"dgraph-alpha-4.dgraph-alpha.crm-test.svc.cluster.local:7080","leader":false,"amDead":false,"lastUpdate":"0","clusterInfoOnly":false,"forceGroupId":false}]