Layer7 "TCPCHK got an empty response at step 1", check duration: 0ms?

Help!
1

Hello

I have a few random Health check for server xxx failed, reason: Layer7 invalid response, info: "TCPCHK got an empty response at step 1", check duration: 0ms, status: 2/3 UP. which sometimes bring down my nodes (after 3 failed tries).

On the node, I see no connection attempts, and the 0ms looks strange (usually it’s in the XXms range).

Any ideas how I can figure out what’s going on?
(i would get one failure every 10-30 in or so, every 2-3 days i get 3 in a row, so nodes go down, then back up)

HAproxy 2.3 config:

backend	xxxxx
    log global
    mode http
    option httpchk
    http-check send meth GET uri /ping.php ver HTTP/1.0 hdr Host example.com
    option http-server-close
    option httpclose
    no option httpclose
    balance	roundrobin
        server a   1.2.3.4:83 check inter 2000 rise 2 fall 3 check weight 12  maxconn 2024 cookie