Cirus not stop watcher when running more process

[thanghl]

2021-01-02 09:37:08 circus[14185] [DEBUG] sending response b'{"status":"ok","time":1609555028.0558147,"id":"496a0d12025642f18521018277d46808"}'
2021-01-02 09:37:08 circus[14185] [DEBUG] sending response b'{"status":"ok","time":1609555028.4822972,"id":"a7a7df5691414dd4828b4486a4b1b312"}'
2021-01-02 09:37:08 circus[14185] [DEBUG] sending response b'{"status":"ok","time":1609555028.8957918,"id":"3e1a60a5c85a4f8dba2bb9dc06c77e1c"}'
2021-01-02 09:37:09 circus[14185] [DEBUG] sending response b'{"status":"ok","time":1609555029.3114102,"id":"00cb90566fde401c99378021c18318f4"}'
2021-01-02 09:37:09 circus[14185] [DEBUG] sending response b'{"status":"error","reason":"arbiter is already running watcher_stop command","tb":null,
When i run more watcher and stop sometime broken, circus version 0.17.1 os centos 7
/usr/local/bin/circusctl stop mo
/usr/local/bin/circusctl stop tu
/usr/local/bin/circusctl stop we
/usr/local/bin/circusctl stop th
/usr/local/bin/circusctl stop _fr
/usr/local/bin/circusctl stop sa
/usr/local/bin/circusctl start sun