Seems this was my problem too. What I noticed was that docker suddenly could not be run except as root. And none of the usual remedies for that had any effect. Luckily KDEwallet started demanding a login at the same time which pointed me to this bug. Tobias advice above fixed the problem so I think that confirms the diagnosis. Kubuntu 18.04 with KDE Plasma 5.12.7, KDE Frameworks 5.44.0 and Qt 5.9.5.
Seems this was my problem too. What I noticed was that docker suddenly could not be run except as root. And none of the usual remedies for that had any effect. Luckily KDEwallet started demanding a login at the same time which pointed me to this bug. Tobias advice above fixed the problem so I think that confirms the diagnosis. Kubuntu 18.04 with KDE Plasma 5.12.7, KDE Frameworks 5.44.0 and Qt 5.9.5.