Second try fails to prompt for authentication if first was canecelled

Start plasma-discover because there are pending updates.
Click on "Update all".
When the authentication box pops up Cancel it (I've decided I now want to look at some information before continuing).
The box goes away.
Click on "Update all" again. It greys-out all buttons, presumably waiting for an authentication box to return, but *no authentication box is posted*! (Which is the bug)

You have to kill -TERM the process and start again.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: plasma-discover 5.12.6-0ubuntu0.1
ProcVersionSignature: Ubuntu 4.15.0-36.39-generic 4.15.18
Uname: Linux 4.15.0-36-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: KDE
Date: Sun Oct 14 00:47:04 2018
InstallationDate: Installed on 2017-11-01 (346 days ago)
InstallationMedia: Kubuntu 17.10 "Artful Aardvark" - Release amd64 (20171017.1)
SourcePackage: plasma-discover
UpgradeStatus: Upgraded to bionic on 2018-05-02 (164 days ago)