title: Docker build works fine on ArchLinux (docker 20.10.5) but fails on Ubuntu (docker 19.03.8)
body: <p>I have this very simple Dockerfile:</p>
  <pre><code>FROM ubuntu:21.04
  
  ENV DEBIAN_FRONTEND=noninteractive
  
  RUN apt-get update &amp;&amp; apt-get upgrade -y \
      &amp;&amp; apt-get install -y curl doxygen git build-essential python3-dev python3-venv python3-setuptools clang clang-tidy clang-format cppcheck clazy \
      &amp;&amp; apt-get install -y npm nodejs cmake ninja-build qtbase5-dev qtdeclarative5-dev \
      &amp;&amp; apt-get install -y icecc qtlocation5-dev qtpositioning5-dev libqt5websockets5-dev qtwebengine5-dev libqt5webchannel5-dev qtbase5-private-dev \
      &amp;&amp; apt-get install -y libdw-dev \
      &amp;&amp; apt-get clean \
      &amp;&amp; rm -rf /var/lib/apt/lists/*
      ...
  </code></pre>
  <p>This builds totally fine in ArchLinux with Docker 20.10.5 but generates the following error in Ubuntu with Docker 19.03.8:</p>
  <pre><code>Setting up hunspell-en-us (1:2019.10.06-1) ...
  Error: update-dictcommon-hunspell not present or executable. Missing dependency on dictionaries-common?
  dpkg: error processing package hunspell-en-us (--configure):
   installed hunspell-en-us package post-installation script subprocess returned error exit status 1
  </code></pre>
  <p>and many other errors as a consequence of this one.</p>
  <p>My question is: aren't docker builds expected to be reproducible in any environment? Both builds are using the same base image and, therefore, I assume they are also using the same package repositories when building on Ubuntu and ArchLinux. What's the reason for working in ArchLinux and failing on Ubuntu?</p>