Segfault (exit 139) opening any comic — crash trace points to Qt6DBus/Qt6Core, persists after clean reinstall

[u1nlore-svg]

YACReader version: 10.2.0 (Flathub Flatpak)
Distro: Linux Mint
Install method: Flatpak (flathub)

The reader crashes with a segfault (exit code 139) every time I try
to open a comic — happens with both .cbz and .cbr files, in
different folders/drives, so it's not archive-format or
file-specific. YACReaderLibrary (the library/browser component)
works fine — only the reader crashes.

It worked fine for the first few days after installing, then
started crashing consistently. It still crashes after a full clean
reinstall:
flatpak uninstall com.yacreader.YACReader
rm -rf ~/.var/app/com.yacreader.YACReader
flatpak install flathub com.yacreader.YACReader

Steps to reproduce:

1. flatpak run com.yacreader.YACReader
2. Open any .cbz or .cbr file
3. App crashes right as it tries to display page 1

Debug log (last lines before crash):
DEBUG opening archive: "example.cbz"
DEBUG # of pages in archive: 35
DEBUG closing archive.
DEBUG current pos = [ 0 ] seeking to [ 0 ]
DEBUG closing archive.
[process exits with code 139]

Partial backtrace from coredumpctl (no debug symbols available for
the Flatpak build, so frames are unresolved, but library names are
visible):
#0 ?? ()
#1 libglib-2.0.so.0
#2 libQt6Core.so.6.11.1
#3 libQt6Core.so.6.11.1
#4 libQt6Core.so.6.11.1
#5 libQt6DBus.so.6.11.1
#6 libQt6Core.so.6.11.1
#7 libc.so.6

This points toward a crash inside Qt's DBus handling rather than
image decoding itself.

Already tried, no change in behavior:

• LIBGL_ALWAYS_SOFTWARE=1
• flatpak override --user --filesystem=host (and later --reset)
• Full uninstall + remove ~/.var/app data + reinstall
• Different files, folders, and drives — same crash every time

System: Linux Mint (Cinnamon), X11