Problems upgrading to proposed base-files 10.1ubuntu2.1

[PhotonQyv]

On upgrading to the new bionic-proposed version of base-files (10.1ubuntu2.1)

I got the following output:

sudo apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  base-files
1 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.
Need to get 58.0 kB of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://gb.archive.ubuntu.com/ubuntu bionic-proposed/main amd64 base-files amd64 10.1ubuntu2.1 [58.0 kB]
Fetched 58.0 kB in 0s (376 kB/s)
Reading changelogs... Done
(Reading database ... 771574 files and directories currently installed.)
Preparing to unpack .../base-files_10.1ubuntu2.1_amd64.deb ...
Warning: Stopping motd-news.service, but it can still be activated by:
  motd-news.timer
Unpacking base-files (10.1ubuntu2.1) over (10.1ubuntu2) ...
Setting up base-files (10.1ubuntu2.1) ...
Installing new version of config file /etc/issue ...
Installing new version of config file /etc/issue.net ...
Installing new version of config file /etc/lsb-release ...
motd-news.service is a disabled or a static unit, not starting it.
Processing triggers for install-info (6.5.0.dfsg.1-2) ...
Processing triggers for plymouth-theme-ubuntu-text (0.9.3-1ubuntu7) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for cracklib-runtime (2.9.2-5build1) ...
Processing triggers for man-db (2.8.3-2) ...
Processing triggers for plymouth-theme-kubuntu-text (1:18.04ubuntu11) ...
dpkg: warning: version '/etc/lsb-release' has bad syntax: version number does not start with a digit
rmdir: failed to remove '/lib/plymouth/': No such file or directory
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.130ubuntu3.2) ...
update-initramfs: Generating /boot/initrd.img-4.17.8-041708-generic
qyv@Twinkle:~$ ll /lib/plymouth/
ls: cannot access '/lib/plymouth/': No such file or directory
qyv@Twinkle:~$ ll /lib/plymouth*
ls: cannot access '/lib/plymouth*': No such file or directory

------------

Description: Ubuntu 18.04.1 LTS
Release: 18.04

apt-cache policy base-files
base-files:
  Installed: 10.1ubuntu2.1
  Candidate: 10.1ubuntu2.1
  Version table:
 *** 10.1ubuntu2.1 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     10.1ubuntu2 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic/main amd64 Packages