Non existent audio sink device is selected by default

I've configured by headset as the default device in KDE sound settings by dragging it to the top in the list of available sink devices because I want to have it as the default device when it is connected. But when I reboot the system and even the headset is not connected the headset is chosen by default anyway.
The expected behavior is that pulseaudio selects the first connected/available device in the list of sink devices.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.14
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: KDE
Date: Sun Jul 24 08:30:09 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2016-07-15 (8 days ago)
InstallationMedia: Kubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=de_AT:de
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_AT.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
Symptom: dist-upgrade
UpgradeStatus: No upgrade log present (probably fresh install)