SUMMARY
I updated skrooge nightly flatpak and ran it with my .skg file, and it crashed after the splash screen and before the main window appeared. I repeated this and it happened again, but it didn't happen if I opened an older empty .skg file. I then ollowed https://docs.flatpak.org/en/latest/debugging.html to install debug packages and run under gdb, and the flatpak didn't crash on my .skg file. Moreover, when I then ran the Skrooge flatpak the same way as it crashed, it didn't crash!

STEPS TO REPRODUCE
1. Run nightly skrooge flatpak on large .skg file last saved 2025-02-20

OBSERVED RESULT
Skrooge's 25.1.1 splash screen window with rubber duck appears, then crash. Terminal shows
    ##WARNING: Another action already registered for identifier edit_copy
    ##WARNING: Another action already registered for identifier edit_expandall
    ##WARNING: Another action already registered for identifier edit_collapseall
    ##FATAL: ASSERT failure in QList<T>::at: "index out of range", file /usr/include/QtCore/qlist.h, line 571

The abrt utility reports that skrooge has crashed. It declines to make a bug report because, roughly, "The backtrace is low quality". But I followed https://docs.flatpak.org/en/latest/debugging.html#getting-stacktraces-from-a-crash and it shows the qt_assert_x() from QList<KaboutPerson> called from SKGMainPanel::SKGMainPanel() :

...
#8  0x00007f5b55e9d366 in qt_assert_x (where=where@entry=0x7f5b577528ad "QList<T>::at", what=what@entry=0x7f5b5775289a "index out of range", file=file@entry=0x7f5b5775287e "/usr/include/QtCore/qlist.h", line=line@entry=571) at global/qglobal.cpp:3400
#9  0x00007f5b576b3e9b in QList<KAboutPerson>::at (i=0, this=0x7fff3f3a9660) at /usr/include/QtCore/qlist.h:571
#10 0x00007f5b576b4435 in QList<KAboutPerson>::at (this=<optimized out>, i=<optimized out>) at /run/build/skrooge/skgbasegui/skgmainpanel.cpp:782
#11 SKGMainPanel::SKGMainPanel (this=this@entry=0x562b2878da60, iSplashScreen=iSplashScreen@entry=0x562b2870c310, iDocument=iDocument@entry=0x7fff3f3a9900, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /run/build/skrooge/skgbasegui/skgmainpanel.cpp:420
...

The backtrace from the second crash was basically the same.

EXPECTED RESULT
No crash.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.3.1
KDE Plasma Version: 5.116.0
KDE Frameworks Version: 5.116.0
Qt Version: 5.15.15 on Wayland

ADDITIONAL INFORMATION

I tried opening an old small .skg file and after Skrooge displayed a message about migrating it, Skrooge seemed to work.

I recently submitted a merge request for .flatpak-manifest.json to "Update KDE Platform runtime and io.qt.qtwebengine.BaseApp to 5.15-24.08", maybe that broke something?