ubiquity crash on whoopsie removal, Xubuntu 21.04 minimal install

Xubuntu hirsute 20201213 minimal install crashed on whoopsie removal but finished installing. This is 1907951 with hopefully more crash information.

Related logs identified:
Dec 13 12:37:05 xubuntu ubiquity: Purging configuration files for whoopsie (0.2.73) ...
Dec 13 12:37:05 xubuntu ubiquity: #015
Dec 13 12:37:05 xubuntu ubiquity: Running in chroot, ignoring command 'daemon-reload'#015
Dec 13 12:37:05 xubuntu ubiquity: message repeated 2 times: [ Running in chroot, ignoring command 'daemon-reload'#015]
Dec 13 12:37:05 xubuntu ubiquity: rm:
Dec 13 12:37:05 xubuntu ubiquity: cannot remove '/var/lib/whoopsie/whoopsie-id'
Dec 13 12:37:05 xubuntu ubiquity: : No such file or directory
Dec 13 12:37:05 xubuntu ubiquity: #015
Dec 13 12:37:05 xubuntu ubiquity: dpkg: error processing package whoopsie (--purge):
Dec 13 12:37:05 xubuntu ubiquity: #015
Dec 13 12:37:05 xubuntu ubiquity: installed whoopsie package post-removal script subprocess returned error exit status 1
Dec 13 12:37:05 xubuntu ubiquity: #015

Looks like it's a bug in the postrm script:
#! /bin/sh

set -e

#DEBHELPER#

if [ "$1" = "purge" ]; then
        deluser --quiet --system whoopsie > /dev/null || true
        chmod g-s /var/crash >/dev/null 2>&1
        chgrp root /var/crash >/dev/null 2>&1
        rm /var/lib/whoopsie/whoopsie-id >/dev/null
fi

exit 0

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: ubiquity 21.04.3
ProcVersionSignature: Ubuntu 5.8.0-25.26-generic 5.8.14
Uname: Linux 5.8.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu55
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.456
Date: Sun Dec 13 07:40:33 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/xubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Xubuntu 21.04 "Hirsute Hippo" - Alpha amd64 (20201213)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
RebootRequiredPkgs:
 linux-image-5.8.0-25-generic
 linux-base
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)