If the package appmenu-qt5 is installed, Plasma is broken. This is due to appmenu-qt5 installing a /etc/profile.d/appmenu-qt5.sh which sets the QT_QPA_PLATFORMTHEME env variable. By having that loaded into the session the qpt plugin provided by plasma-integration won't be loaded.
If the package appmenu-qt5 is installed, Plasma is broken. This is due to appmenu-qt5 installing a /etc/profile. d/appmenu- qt5.sh which sets the QT_QPA_ PLATFORMTHEME env variable. By having that loaded into the session the qpt plugin provided by plasma-integration won't be loaded.