Haproxy 1.8.x url_param issue in http2

Help!
13

It’s absolutely minimal valid config:

global
  daemon
  nbproc  1
  pidfile  /var/run/haproxy.pid
  stats  socket /var/lib/haproxy/stats uid 0 gid 0 mode 0440 process 1
  tune.ssl.default-dh-param  2048

defaults
  timeout  connect 302s
  timeout  client 302s
  timeout  server 302s

frontend https
  bind 0.0.0.0:443 ssl crt /etc/ssl/server.pem alpn h2,http/1.1
  mode http
  default_backend http2_backend

backend http2_backend
  mode http
  balance url_param bh
  #balance roundrobin
  server http1.1 127.0.0.1:81 check

but the same result