My setup has slush, kano, & solo.ckpool as proxies 0,1, & 2 respectively. Kano lost connectivity or restarted the pool a few hours ago and the proxies switched to it and stayed there for a few hours until I noticed and restarted them.
[2017-03-15 18:11:57.400] Proxy:{"current": 0, "active": 3, "total": 3}
[2017-03-15 18:12:34.834] Proxy 1:0 stratum+tcp://stratum.kano.is:3333 failed to read_socket_line in proxy_recv
[2017-03-15 18:12:34.834] Proxy 1:0 stratum+tcp://stratum.kano.is:3333 epoll hangup in proxy_recv
[2017-03-15 18:12:34.834] Proxy 1:stratum+tcp://stratum.kano.is:3333 failed, attempting reconnect
[2017-03-15 18:12:39.010] Found notify for new proxy 1:0 with enonce 159c0d5d nonce2len 8
[2017-03-15 18:12:39.010] Got updated subscribe for proxy 1
[2017-03-15 18:12:39.010] Upstream pool stratum+tcp://stratum.kano.is:3333 1 extranonce2 length 8, max proxy clients 4294967296
[2017-03-15 18:12:39.010] Stratifier setting active proxy to 1
Slush was still up and running fine the whole time judging by the logs. Is there a way to prevent this switch from happening on a pool restart?