When I try to start phantomjs from yakuake, it fails with this error: This application failed to start because it could not find or load the Qt platform plugin "xcb". Phantomjs is compiled without the xcb plugin, it has its own plugin called "phantom". QT_QPA_PLATFORM is set to xcb in my yakuake environment. It's not set in konsole, so phantomjs works there. It looks like yakuake is leaking it into the environment somehow. I diffed the env of konsole and yakuake, QT_QPA_PLATFORM was the only extra variable in yakuake (there were a couple other differences in values, e.g. WINDOWID, and KONSOLE_DBUS_WINDOW was missing from yakuake).
I don't have QT_QPA_PLATFORM in my Yakuake environment. My guess would be: - It's set in some file your shell ends up sourcing when run by Yakuake but not Konsole (e.g. due to differences in the profile). - Your distro applied some patch to Yakuake to force it to use Xwayland on Wayland systems.
It's using the same profile as konsole. I'm using Ubuntu 17.04, I'll check if there are any patches in the debian package.
Which version did you test? I have 3.0.2, and this change in 3.0.3 removed a qputenv("QT_QPA_PLATFORM"): https://phabricator.kde.org/R369:36ba26ec981e1a6896ef860e625791cfb42c32c5
Upgrading to 3.0.4 fixed it.