First discovered when using Latte Dock and determined to be an error with the taskmanager by conversation with the creator of Latte Dock. The error also occurs with some desktop-based widgets. 

The files modified are kdesystemsettings.desktop and systemsettings.desktop. The Exec properties are changed, with modified LANG environment variables. "nohup" and "&" are appended to the beginning and end of the Exec command. I have also tried removing nohup. The following error message is given before the application launches: `KDEInit: Cannot start "/bin/sh"`

Here is a sample Exec line from one of the .desktop files (they are identical):
Exec=english systemsettings5 &

Here is the "english" command:
#!/bin/bash

eval 'LANG=C "$@"'

Here is a line to the original issue: https://github.com/psifidotos/Latte-Dock/issues/374

A snippet of output from a comment on the issue regarding kdeinit5 in sharper specificity:

kdeinit5: opened connection to :0
kdeinit5: Got EXT_EXEC '/bin/sh' from launcher.
kdeinit5: preparing to launch '/bin/sh'
kdeinit5: PID 5518 terminated.

Exhaustive output and more detailed context can be found by following the comments on the aforementioned issue. 
The exact iso used to write my installation of KDE: neon-devedition-gitstable-20170321-1047-amd64.iso
Below are command output dumps.

Output of "uname -a":


Linux cm-lx-pc 4.8.0-46-generic #49~16.04.1-Ubuntu SMP Fri Mar 31 14:51:03 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux


Output of "kdeinit5 --version":


Qt: 5.7.1
KDE: 5.33.0


Output of "plasmashell --version":


QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
plasmashell 5.9.4


Output of "qtdiag":


QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
Qt 5.7.1 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 5.4.0 20160609) on "xcb" 
OS: KDE neon Developer Edition [linux version 4.8.0-46-generic]

Architecture: x86_64; features: SSE2 SSE3 SSSE3 SSE4.1

Environment:

Features: QT_NO_EXCEPTIONS QT_NO_ZLIB

Library info:
  PrefixPath: /usr
  DocumentationPath: /usr/share/qt5/doc
  HeadersPath: /usr/include/x86_64-linux-gnu/qt5
  LibrariesPath: /usr/lib/x86_64-linux-gnu
  LibraryExecutablesPath: /usr/lib/x86_64-linux-gnu/qt5/libexec
  BinariesPath: /usr/lib/x86_64-linux-gnu/qt5/bin
  PluginsPath: /usr/lib/x86_64-linux-gnu/qt5/plugins
  ImportsPath: /usr/lib/x86_64-linux-gnu/qt5/imports
  Qml2ImportsPath: /usr/lib/x86_64-linux-gnu/qt5/qml
  ArchDataPath: /usr/lib/x86_64-linux-gnu/qt5
  DataPath: /usr/share/qt5
  TranslationsPath: /usr/share/qt5/translations
  ExamplesPath: /usr/lib/x86_64-linux-gnu/qt5/examples
  TestsPath: /usr/tests
  SettingsPath: /etc/xdg

Standard paths [*...* denote writable entry]:
  DesktopLocation: "Desktop" */root/Desktop*
  DocumentsLocation: "Documents" */root/Documents*
  FontsLocation: "Fonts" */root/.fonts*
  ApplicationsLocation: "Applications" */root/.local/share/applications* /usr/local/share/applications /usr/share/applications
  MusicLocation: "Music" */root/Music*
  MoviesLocation: "Movies" */root/Videos*
  PicturesLocation: "Pictures" */root/Pictures*
  TempLocation: "Temporary Directory" */tmp*
  HomeLocation: "Home" */root*
  AppLocalDataLocation: "Application Data" */root/.local/share/QtProject/qtdiag* /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag
  CacheLocation: "Cache" */root/.cache/QtProject/qtdiag*
  GenericDataLocation: "Shared Data" */root/.local/share* /usr/local/share /usr/share
  RuntimeLocation: "Runtime" */tmp/runtime-root*
  ConfigLocation: "Configuration" */root/.config* /etc/xdg
  DownloadLocation: "Download" */root/Downloads*
  GenericCacheLocation: "Shared Cache" */root/.cache*
  GenericConfigLocation: "Shared Configuration" */root/.config* /etc/xdg
  AppDataLocation: "Application Data" */root/.local/share/QtProject/qtdiag* /usr/local/share/QtProject/qtdiag /usr/share/QtProject/qtdiag
  AppConfigLocation: "Application Configuration" */root/.config/QtProject/qtdiag* /etc/xdg/QtProject/qtdiag

File selectors (increasing order of precedence):
  de_DE unix linux neon

Network:
  Using "OpenSSL 1.0.2g  1 Mar 2016", version: 0x1000207f

Platform capabilities: ThreadedPixmaps OpenGL WindowMasks MultipleWindows ForeignWindows NonFullScreenWindows NativeWidgets WindowManagement SyncState RasterGLSurface SwitchableWidgetComposition

Style hints:
  mouseDoubleClickInterval: 400
  mousePressAndHoldInterval: 800
  startDragDistance: 10
  startDragTime: 500
  startDragVelocity: 0
  keyboardInputInterval: 400
  keyboardAutoRepeatRate: 30
  cursorFlashTime: 1000
  showIsFullScreen: 0
  showIsMaximized: 0
  passwordMaskDelay: 0
  passwordMaskCharacter: U+25CF
  fontSmoothingGamma: 1
  useRtlExtensions: 0
  setFocusOnTouchRelease: 0
  tabFocusBehavior: Qt::TabFocusBehavior(TabFocusAllControls) 
  singleClickActivation: 0

Additional style hints (QPlatformIntegration):
  ReplayMousePressOutsidePopup: 0

Theme:
  Available    : generic
  Styles       : Fusion,Windows
  System font  : "Sans Serif" 9

Fonts:
  General font : "Sans Serif" 9
  Fixed font   : "monospace" 9
  Title font   : "DejaVu Sans" 12
  Smallest font: "DejaVu Sans" 12

Palette:
  WindowText: #ff000000
  Button: #ffefebe7
  Light: #ffffffff
  Midlight: #ffcbc7c4
  Dark: #ff9f9d9a
  Mid: #ffb8b5b2
  Text: #ff000000
  BrightText: #ffffffff
  ButtonText: #ff000000
  Base: #ffffffff
  Window: #ffefebe7
  Shadow: #ff767472
  Highlight: #ff308cc6
  HighlightedText: #ffffffff
  Link: #ff0000ff
  LinkVisited: #ffff00ff
  AlternateBase: #fff7f5f3
  NoRole: #ff000000
  ToolTipBase: #ffffffdc
  ToolTipText: #ff000000

Screens: 2, High DPI scaling: inactive
# 0 "HDMI-1" Depth: 24 Primary: yes
  Geometry: 1920x1080+1280+0 Available: 1920x1054+1280+26
  Virtual geometry: 3200x1080+0+0 Available: 3200x1054+0+26
  2 virtual siblings
  Physical size: 710x400 mm  Refresh: 60 Hz Power state: 0
  Physical DPI: 68.6873,68.58 Logical DPI: 85,85 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 1
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

# 1 "VGA-1" Depth: 24 Primary: no
  Geometry: 1280x1024+0+28 Available: 1280x1024+0+28
  Virtual geometry: 3200x1080+0+0 Available: 3200x1054+0+26
  2 virtual siblings
  Physical size: 376x301 mm  Refresh: 75 Hz Power state: 0
  Physical DPI: 86.4681,86.4106 Logical DPI: 85,85 Subpixel_None
  DevicePixelRatio: 1 Pixel density: 1
  Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

LibGL Vendor: Intel Open Source Technology Center
Renderer: Mesa DRI Intel(R) Q45/Q43 
Version: 2.1 Mesa 12.0.6
Shading language: 1.20
Format: Version: 2.1 Profile: 0 Swap behavior: 0 Buffer size (RGB): 8,8,8