I got this bug again after upgrading to qt5 5.15.8+dfsg-6. The same behavior of plasma screen locker freezing and showing the message to use loginctl to unlock.
Downgrading to 5.15.8+dfsg-5 solves it. Since it affects this package again, I'm reopening this bug report. -- Adilson dos Santos Dantas http://www.adilson.net.br http://twitter.com/adilsond
