Leaking zombie processes

[Nakilon]

FROM ruby:2.7-alpine
RUN gem update bundler
RUN apk add build-base chromium

require "ferrum"

loop do
  puts "loop"
  browser = Ferrum::Browser.new headless: true, browser_options: {"no-sandbox" => nil}
  browser.go_to "http://t.me/tomsk_region70"
  sleep 10
ensure
  browser&.quit
end

$ docker run --rm -d -v $(pwd):/app -w /app -p 8002:8000 --name temp chromium sh -c "gem install ferrum && ruby app.rb"

$ docker exec temp ps aux | grep chrome
root        41  0.1  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root        42  0.1  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root        62  3.6  0.0      0     0 ?        Z    05:45   0:01 [chrome] <defunct>
root        64  0.1  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root        71 15.8  0.0      0     0 ?        Z    05:45   0:06 [chrome] <defunct>
root        98  0.1  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root        99  0.2  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root       115  5.5  0.0      0     0 ?        Z    05:45   0:01 [chrome] <defunct>
root       118  0.1  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root       124 24.7  0.0      0     0 ?        Z    05:45   0:06 [chrome] <defunct>
root       155  0.3  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root       156  0.3  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root       173  9.6  0.0      0     0 ?        Z    05:45   0:01 [chrome] <defunct>
root       175  0.3  0.0      0     0 ?        Z    05:45   0:00 [chrome] <defunct>
root       181 44.0  0.0      0     0 ?        Z    05:45   0:06 [chrome] <defunct>

[Nakilon]

Seems to be resolved by https://docs.docker.com/compose/compose-file/compose-file-v3/#init
I'll close when I'm sure.