Crash upon clicking checkbox next to KDE style in settings

[foemre]

Kubuntu 21.04
KDE version 5.21
I tried both installing PyQt5 from pip and building Qt 5.15.2 from source.

I receive the following upon clicking the checkbox next to KDE in this screen:

lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by lookandfeeltool)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5KCMUtils.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5KDELibs4Support.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5QuickAddons.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libkworkspace5.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5KIOGui.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5JobWidgets.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Service.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Package.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5IconThemes.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5ConfigWidgets.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5ConfigGui.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5CoreAddons.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5I18n.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5WindowSystem.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libQt5X11Extras.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5ConfigCore.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libQt5QuickWidgets.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5XmlGui.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Declarative.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Auth.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5AuthCore.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5GuiAddons.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5ItemViews.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5KIOFileWidgets.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Notifications.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Parts.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Solid.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5TextWidgets.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5KIOWidgets.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Completion.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5KIOCore.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Crash.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libQt5PrintSupport.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Codecs.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5GlobalAccel.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libstdc++.so.6: version GLIBCXX_3.4.28' not found (required by /lib/x86_64-linux-gnu/libQt5Xml.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libstdc++.so.6: version GLIBCXX_3.4.26' not found (required by /lib/x86_64-linux-gnu/libQt5Xml.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libQt5Xml.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5DBusAddons.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Archive.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Attica.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5Bookmarks.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libQt5TextToSpeech.so.5)
lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5SonnetUi.so.5) lookandfeeltool: /tmp/_MEIQ0un0r/libQt5Core.so.5: version Qt_5.15' not found (required by /lib/x86_64-linux-gnu/libKF5SonnetCore.so.5)
Traceback (most recent call last):
File "/home/daeh/Application/Yin-Yang-Build/src/gui.py", line 147, in toggleKdeFields
File "/home/daeh/Application/Yin-Yang-Build/src/gui.py", line 129, in getKdeThemes
File "/usr/lib/python3.6/subprocess.py", line 336, in check_output
File "/usr/lib/python3.6/subprocess.py", line 418, in run
subprocess.CalledProcessError: Command '['lookandfeeltool', '-l']' returned non-zero exit status 1.
Aborted (core dumped)`

[l0drex]

This error is thrown by the command line application lookandfeeltool. Running it from the terminal should produce the same error.

Try installing Qt5 from your package manager

[quanta-kt]

I am experiencing the same problem

Running it from the terminal should produce the same error.

Running lookandfeeltool -l from terminal does not give me any errors.
Output:

$ lookandfeeltool -l
org.kde.breezetwilight.desktop
org.kde.breeze.desktop
org.kde.breezedark.desktop
$ echo $?           
0

EDIT: edited output to include exit code