HAProxy community

Disable-on-404 seems not work

can haproxy ensure every call to backend server is successful when one of backend server is down ?
i tried to use disable-on-404 parameter.

mode http
option httpchk
http-check expect status 200
http-check disable-on-404
balance roundrobin
server host1 11.11.11.11:9080 check inter 2000 rise 1 fall 2
server host2 11.11.11.12:9080 check inter 2000 rise 1 fall 2

but when 11.11.11.11 is down, we still can many 404 errors on 11.11.11.11.

2020-08-25T11:58:14 11.11.11.11:9080 200 POST /tsturl1 HTTP/1.1 2274
2020-08-25T11:58:14 11.11.11.22:9080 200 POST /tsturl1 HTTP/1.1 448
2020-08-25T11:58:14 11.11.11.11:9080 503 POST /tsturl1 HTTP/1.1 0
2020-08-25T11:58:14 11.11.11.11:9080 404 POST /tsturl1 HTTP/1.1 0
2020-08-25T11:58:14 11.11.11.11:9080 200 POST /tsturl1 HTTP/1.1 1503
2020-08-25T11:58:16 11.11.11.22:9080 200 POST /tsturl1 HTTP/1.1 617
2020-08-25T11:58:16 11.11.11.11:9080 404 POST /tsturl1 HTTP/1.1 0
2020-08-25T11:58:16 11.11.11.22:9080 200 POST /tsturl1 HTTP/1.1 618
2020-08-25T11:58:16 11.11.11.11:9080 404 POST /tsturl1 HTTP/1.1 0

2020-08-25T11:58:16 host1 is DOWN, reason: Layer7 wrong status, code: 404, info: “Not Found”, check duration: 0ms. 1 active and 0 backup servers left. 0 sessions active, 0 requeued, 0 remaining in queue. 2020-08-25T11:58:16 11.11.11.22:9080 200 POST /tsturl1 HTTP/1.1 645

from the design , when 404 was found, no more access will be directed to this server, but from test, it’s not the truth, can anybody tell me why ?