When I unlock widgets in plasma and hit the hamburger menu on the panel for the settings bar, plasma crashes as soon as that bar closes (slides down). This makes adding/removing widgets impossible to the panel. In the case of removing, a notification pops up telling me it's removed (and that I can undo this), but as soon as the bar closes, plasma crashes, and the widget reappears in the panel.

(Sorry, I don't know the correct name for the sliding settings bar which may make this bug hard to find for others.)