Confirmed on clean install of Kubuntu 18.04.3. It seems to be a bug with kdesu rather than muon itself: kdesu freezes if given a wrong password also calling other commands, for example when launching KDE partition manager from the KDE menu.
Confirmed on clean install of Kubuntu 18.04.3.
It seems to be a bug with kdesu rather than muon itself: kdesu freezes if given a wrong password also calling other commands, for example when launching KDE partition manager from the KDE menu.