It doesn't look like any relevant commits have been made since you opened this issue, but when experiencing the same or a similar issue I amended my docker-compose.yaml from

labels:
  autoheal: true

to

labels:
  autoheal: "true"

after which docker inspect <name> | grep autoheal returned the string with a lowercase 't' and the autoheal container picks up 'unhealthy' containers and restarts them succesfully. Are you still encountering this problem now?

from docker-autoheal.

I've ran onto this issue myself, causing investigation into why autoheal is not doing any correction of unhealthy containers. And while the label workaround (described above) has seemed to provided relief, as of the latest release of docker-compose, an new adjustment of no space between autoheal and "true" was required for me. If a space was included, docker-compose would complain about an invalid docker-compose.yaml file format. Details and sample below.

docker-compose version

docker-compose version 1.27.4, build 40524192
docker-py version: 4.3.1
CPython version: 3.7.7
OpenSSL version: OpenSSL 1.1.0l 10 Sep 2019

docker-compose.yaml
...
labels:
- autoheal:"true"
- autoheal.stop.timeout=60

docker inspect | grep autoheal

            "autoheal.stop.timeout": "60",
            "autoheal:\"true\"": "",	  

from docker-autoheal.

Is this supposed to be a container or service label? I'm having issues getting my stack deploy to not consider it "unsupported". I can add it manually using Portainer (which I'm trying to phase out), so could someone please let me know the proper placement? It seems that under deploy: it would be for the service. I also tried using build: but that was ignored. Here's pihole for reference.

services: 
  pihole: 
    deploy: 
      placement: 
        constraints: 
          - "node.role == manager"
    dns: 
      - "127.0.0.1"
    environment: 
      - TZ=America/New_York
      - "DNS1=10.47.20.1#5053"
      - WEBPASSWORD=xxxxxxxx
      - ServerIP=10.47.20.2
    hostname: pihole.xxxxxxxx.home
    image: pihole/pihole
    ports: 
      - "53:53"
      - "53:53/udp"
      - "67:67/udp"
      - "80:80"
    volumes: 
      - "/docker/pihole/pihole/:/etc/pihole/"
      - "/docker/pihole/dnsmasq.d/:/etc/dnsmasq.d/"

from docker-autoheal.