update-manager display a blank window in version 1:20.04.10.2

[dominix]

First I have upgraded update-manager-core update-manager python3-update-manager to version 1:20.04.10.2 on my Focal LTS 20.04 machine

then after "apt update" update-manager shows up to propose the upgrade of the system.
this windows is correctly displayed, but if I click on "upgrade" then a new empty windows appear and do not show nothing and the process of upgrading is stopped.

the only way to retrieve functionnality is to roll-back to version 1:20.04.10.1

"sudo apt install --reinstall update-manager-core=1:20.04.10.1 update-manager=1:20.04.10.1 python3-update-manager=1:20.04.10.1"

then things are back to normal.

I have tested this process on Three focal machine with same results, so it looks 1:20.04.10.2 clearly has a bug.

thanks for your continuous support. regards.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: update-manager 1:20.04.10.1
ProcVersionSignature: Ubuntu 5.4.0-59.65-generic 5.4.78
Uname: Linux 5.4.0-59-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: MATE
Date: Fri Jan 8 08:47:50 2021
GsettingsChanges:
 b'com.ubuntu.update-manager' b'window-width' b'657'
 b'com.ubuntu.update-manager' b'launch-count' b'235'
 b'com.ubuntu.update-manager' b'first-run' b'false'
 b'com.ubuntu.update-manager' b'launch-time' b'int64 1610131614'
 b'com.ubuntu.update-manager' b'window-height' b'419'
PackageArchitecture: all
SourcePackage: update-manager
UpgradeStatus: Upgraded to focal on 2020-06-23 (199 days ago)

[roots (roots)]

I can confirm this bug:

Ubuntu Focal 20.04 LTS
update-manager 1:20.04.10.2.
5.10.0-6.2-liquorix-amd64
MATE Desktop

I also confirm that the rollback to 1:20.04.10.1 solves the issue for me as well - thanks a lot @dominix for this pointer!

Cheers,
r.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.