I think the core of this is fixed, but there's some situations still where it triggers -- here's a new reproducer that can still trigger it reliably with Docker (since I can't reproduce with the simplified steps in #31 anymore):

```
$ docker pull ubuntu:20.04

20.04: Pulling from library/ubuntu
Digest: sha256:bc2f7250f69267c9c6b66d7b6a81a54d3878bb85f1ebb5f951c896d13e6ba537
Status: Image is up to date for ubuntu:20.04
docker.io/library/ubuntu:20.04

$ docker run --rm ubuntu:20.04 sh -c 'dpkg --add-architecture i386 && apt-get update -qq && apt-get install -y libc6:i386 libfontconfig1:i386 libgl1-mesa-dri:i386 libgl1-mesa-glx:i386'

Reading package lists...
Building dependency tree...
Reading state information...
The following additional packages will be installed:
  fontconfig-config fonts-dejavu-core gcc-10-base gcc-10-base:i386
  libatomic1:i386 libbsd0:i386 libcrypt1:i386 libdrm-amdgpu1:i386
  libdrm-common libdrm-intel1:i386 libdrm-nouveau2:i386 libdrm-radeon1:i386
  libdrm2:i386 libedit2:i386 libelf1:i386 libexpat1:i386 libffi7:i386
  libfreetype6:i386 libgcc-s1 libgcc-s1:i386 libgl1:i386 libglapi-mesa:i386
  libglvnd0:i386 libglx-mesa0:i386 libglx0:i386 libidn2-0:i386 libllvm10:i386
  libpciaccess0:i386 libpng16-16:i386 libsensors-config libsensors5:i386
  libstdc++6 libstdc++6:i386 libtinfo6:i386 libunistring2:i386 libuuid1:i386
  libvulkan1:i386 libwayland-client0:i386 libx11-6:i386 libx11-data
  libx11-xcb1:i386 libxau6:i386 libxcb-dri2-0:i386 libxcb-dri3-0:i386
  libxcb-glx0:i386 libxcb-present0:i386 libxcb-randr0:i386 libxcb-sync1:i386
  libxcb1:i386 libxdamage1:i386 libxdmcp6:i386 libxext6:i386 libxfixes3:i386
  libxshmfence1:i386 libxxf86vm1:i386 libzstd1:i386 mesa-vulkan-drivers:i386
  ucf uuid-runtime zlib1g zlib1g:i386
Suggested packages:
  glibc-doc:i386 locales:i386 pciutils:i386 lm-sensors lm-sensors:i386
The following NEW packages will be installed:
  fontconfig-config fonts-dejavu-core gcc-10-base:i386 libatomic1:i386
  libbsd0:i386 libc6:i386 libcrypt1:i386 libdrm-amdgpu1:i386 libdrm-common
  libdrm-intel1:i386 libdrm-nouveau2:i386 libdrm-radeon1:i386 libdrm2:i386
  libedit2:i386 libelf1:i386 libexpat1:i386 libffi7:i386 libfontconfig1:i386
  libfreetype6:i386 libgcc-s1:i386 libgl1:i386 libgl1-mesa-dri:i386
  libgl1-mesa-glx:i386 libglapi-mesa:i386 libglvnd0:i386 libglx-mesa0:i386
  libglx0:i386 libidn2-0:i386 libllvm10:i386 libpciaccess0:i386
  libpng16-16:i386 libsensors-config libsensors5:i386 libstdc++6:i386
  libtinfo6:i386 libunistring2:i386 libuuid1:i386 libvulkan1:i386
  libwayland-client0:i386 libx11-6:i386 libx11-data libx11-xcb1:i386
  libxau6:i386 libxcb-dri2-0:i386 libxcb-dri3-0:i386 libxcb-glx0:i386
  libxcb-present0:i386 libxcb-randr0:i386 libxcb-sync1:i386 libxcb1:i386
  libxdamage1:i386 libxdmcp6:i386 libxext6:i386 libxfixes3:i386
  libxshmfence1:i386 libxxf86vm1:i386 libzstd1:i386 mesa-vulkan-drivers:i386
  ucf uuid-runtime zlib1g:i386
The following packages will be upgraded:
  gcc-10-base libgcc-s1 libstdc++6 zlib1g
4 upgraded, 61 newly installed, 0 to remove and 0 not upgraded.

...

Processing triggers for libc-bin (2.31-0ubuntu9.1) ...
E: Could not configure 'libc6:i386'. 
E: Could not perform immediate configuration on 'libgcc-s1:i386'. Please see man 5 apt.conf under APT::Immediate-Configure for details. (2)
```

I'm certain that list can be made more specific, but I've tried the obvious packages and haven't had much luck in narrowing down much further.