Nano browser randomly(?) crashes

Tested with Qt 5.13.0 Beta 2 on Ubuntu Linux inux 4.18.0-17-generic x86_64.
qt library from online installer.

When launching nano browser the application randomly crashes.
Works ok if I run another web engine example and then nano browser.

5:16:46: Starting /home/anna/Qt/Examples/Qt-5.13.0/webengine/build-quicknanobrowser-Desktop_Qt_5_13_0_GCC_64bit-Debug/quicknanobrowser ...
QML debugging is enabled. Only use this in a safe environment.
QQmlApplicationEngine failed to load component
qrc:/ApplicationRoot.qml:67 Type BrowserWindow unavailable
qrc:/BrowserWindow.qml:421 ".pdfViewerEnabled" is not available due to component versioning.

ASSERT: "!isEmpty()" in file ../../../../5.13.0/gcc_64/include/QtCore/qlist.h, line 359
15:16:46: The program has unexpectedly finished.
15:16:46: The process was ended forcefully.
15:16:47: /home/anna/Qt/Examples/Qt-5.13.0/webengine/build-quicknanobrowser-Desktop_Qt_5_13_0_GCC_64bit-Debug/quicknanobrowser crashed.

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Stack trace:

1 __GI_raise raise.c 50 0x7ffff6361077
2 __GI_abort abort.c 79 0x7ffff6342535
3 qt_message_fatal qlogging.cpp 1904 0x7ffff6752b1c
4 QMessageLogger::fatal qlogging.cpp 888 0x7ffff6752b1c
5 qt_assert qglobal.cpp 3247 0x7ffff675221b
6 QList<QObject *>::first qlist.h 359 0x555555557578
7 main main.cpp 113 0x555555556a18