FTS is failing to shut down "stats" agents on nodes other than where an "index deletion" is received

guides/gradlew --refresh-dependencies testrunner -P jython=/opt/jython/bin/jython -P 'args=-i /tmp/win10-bucket-ops.ini rerun=False,get-cbcollect-info=True,quota_percent=99,crash_warning=True,create_metakv_entries=True -t bucket_collections.collections_rebalance.CollectionsRebalance.test_data_load_collections_with_hard_failover_rebalance_out,nodes_init=5,services_init=kv-fts-kv-kv-kv,nodes_failover=2,bucket_spec=multi_bucket.buckets_for_rebalance_tests_more_collections,data_load_spec=volume_test_load_with_CRUD_on_collections,data_load_stage=before,scrape_interval=5,rebalance_moves_per_node=32,quota_percent=80,skip_validations=True,GROUP=failover_with_collection_crud'

2021-05-10 20:25:16,298 | test  | INFO    | MainThread | [collections_rebalance:setUp:58] Changing scrape interval to 5

2021-05-10 20:25:18,355 | test  | INFO    | MainThread | [cluster_ready_functions:set_rebalance_moves_per_nodes:129] Changed Rebalance settings: {u'rebalanceMovesPerNode': 32}

2021-05-10 20:25:18,355 | test  | INFO    | MainThread | [collections_rebalance:setUp:78] Creating metakv entries start

2021-05-10 20:27:37,470 | test  | INFO    | MainThread | [collections_rebalance:setUp:80] Creating metakv entries end

2021-05-10 20:27:37,474 | test  | INFO    | MainThread | [bucket_ready_functions:perform_tasks_from_spec:4651] Performing scope/collection specific operations

2021-05-10 20:27:44,384 | test  | INFO    | MainThread | [bucket_ready_functions:perform_tasks_from_spec:4741] Done Performing scope/collection specific operations

2021-05-10 20:27:44,589 | test  | INFO    | MainThread | [collections_rebalance:rebalance_operation:388] Starting rebalance operation of type : hard_failover_rebalance_out

2021-05-10 20:27:44,591 | test  | INFO    | MainThread | [collections_rebalance:rebalance_operation:632] failing over nodes [ip:172.23.104.186 port:8091 ssh_username:root, ip:172.23.120.206 port:8091 ssh_username:root]

2021-05-10 20:27:54,937 | test  | ERROR   | pool-5-thread-9 | [rest_client:_http_request:748] POST http://172.23.98.196:8091/controller/failOver body: otpNode=ns_1%40172.23.104.186&allowUnsafe=false headers: {'Accept': '*/*', 'Connection': 'close', 'Authorization': 'Basic QWRtaW5pc3RyYXRvcjpwYXNzd29yZA==\n', 'Content-Type': 'application/x-www-form-urlencoded'} error: 500 reason: unknown ["Unexpected server error, request logged."] auth: Administrator:password

2021-05-10 20:27:54,940 | test  | ERROR   | pool-5-thread-9 | [rest_client:fail_over:1276] ns_1@172.23.104.186 - Failover error: ["Unexpected server error, request logged."]

ERROR

[ns_server:error,2021-05-10T20:27:54.907-07:00,ns_1@172.23.98.196:<0.25585.1>:menelaus_util:reply_server_error:206]Server error during processing: ["web request failed",

                                 {path,"/controller/failOver"},

                                 {method,'POST'},

                                 {type,exit},

                                 {what,

                                  {{function_clause,

                                    [{ns_orchestrator,rebalancing,

                                      [{request_janitor_run,

                                        {bucket,"bucket1"}},

                                       {rebalancing_state,<0.25739.1>,

                                        <0.25737.1>,[],[],[],[],undefined,

                                        ['ns_1@172.23.104.186'],

                                        undefined,failover,

                                        <<"5173d70bbd2afe55f32eb5e976d59df5">>,

                                        undefined,

                                        {<0.25585.1>,

                                         #Ref<0.2378229137.562823169.70811>}}],

                                      [{file,"src/ns_orchestrator.erl"},

                                       {line,887}]},

                                     {gen_statem,loop_state_callback,11,

                                      [{file,"gen_statem.erl"},{line,1120}]},

                                     {proc_lib,init_p_do_apply,3,

                                      [{file,"proc_lib.erl"},{line,249}]}]},

                                   {gen_statem,call,

                                    [{via,leader_registry,ns_orchestrator},

                                     {failover,['ns_1@172.23.104.186'],false},

                                     infinity]}}},

                                 {trace,

                                  [{gen,do_call,4,

                                    [{file,"gen.erl"},{line,177}]},

                                   {gen,do_for_proc,2,

                                    [{file,"gen.erl"},{line,238}]},

                                   {gen_statem,call_dirty,4,

                                    [{file,"gen_statem.erl"},{line,623}]},

                                   {menelaus_web_cluster,handle_failover,1,

                                    [{file,"src/menelaus_web_cluster.erl"},

                                     {line,782}]},

                                   {request_throttler,do_request,3,

                                    [{file,"src/request_throttler.erl"},

                                     {line,58}]},

                                   {menelaus_util,handle_request,2,

                                    [{file,"src/menelaus_util.erl"},

                                     {line,217}]},

                                   {mochiweb_http,headers,6,

                                    [{file,

                                      "/home/couchbase/jenkins/workspace/couchbase-server-unix/couchdb/src/mochiweb/mochiweb_http.erl"},

                                     {line,150}]},

                                   {proc_lib,init_p_do_apply,3,

                                    [{file,"proc_lib.erl"},{line,249}]}]}]