package nfs-kernel-server 1:1.3.4-2.1ubuntu5 failed to install/upgrade: installed nfs-kernel-server package pre-removal script subprocess returned error exit status 2

[Nico Orrù]

Reported by Ubuntu from the desktop.

Fresh install of 18.04.1 via debootstrap from chrooted 17.10 host.

Post-installation steps:

dpkg-getselection -> dpkg-setselection -> apt update-dselect

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: nfs-kernel-server 1:1.3.4-2.1ubuntu5
ProcVersionSignature: Ubuntu 4.15.0-38.41-generic 4.15.18
Uname: Linux 4.15.0-38-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
Date: Tue Oct 23 15:35:27 2018
Df:

ErrorMessage: installed nfs-kernel-server package pre-removal script subprocess returned error exit status 2
Python3Details: /usr/bin/python3.6, Python 3.6.6, python3-minimal, 3.6.5-3ubuntu1
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.3ubuntu0.1
SourcePackage: nfs-utils
Title: package nfs-kernel-server 1:1.3.4-2.1ubuntu5 failed to install/upgrade: installed nfs-kernel-server package pre-removal script subprocess returned error exit status 2
UpgradeStatus: No upgrade log present (probably fresh install)