On 4.9 it worked, but on 4.14 it doesn’t. It’s not working even on 4.15.x
https://bugs.kde.org/show_bug.cgi?id=387454
https://forums.gentoo.org/viewtopic-t-1072222-start-0.html
https://forum.manjaro.org/t/kde-connect-file-browsing-not-working-openrc/22505/19
So look like bug in evdev/udev/whatever
mtp-detect is returning correct results without any error’s
Picture of error
https://imgur.com/a/IeG5uBY