Can't change label for haproxy metrics in Prometheus

I have haproxy internal metrics page as a target for Prometheus. So I get many metrics like this

haproxy_server_http_responses_total{code="1xx",instance="haproxy:8404",job="other",proxy="http_back",server="rest1"}

I want this 'server' label value to be change from rest1 to rest-1 - just add a dash.So, I writed these line into Prometheus scrape config

- job_name: other    scrape_interval: 30s    honor_labels: true    metrics_path: /metrics    params:      match[]:        - '{__name__=~".+"}'    static_configs:      - targets:          - haproxy:8404           - source_labels: [server]        regex: '^(rest)([\d]+)'        replacement: 'rest-${2}'        target_label: server

But nothing happens.Moreover, if I do smth like this

  - source_labels: [job]    regex: '^other'    replacement: 'newvalue'    target_label: server2

It's ok - it creates new label server2

After some research I realized I can use any inernal labes for relabeling except those which were added by haproxy.

What I'm doing wrong? Maybe haproxy added label can not be relabled?