Comment # 8 on bug 1208188 from Fabian Vogt

Apparently it's a glibc change after all.

libqt5-qtbase and libqt5-qtdeclarative are built without SSE2 support but
libQt5Core5.so.5, libQt5Gui5.so.5 and libQt5Qml5.so.5 are built separately with
SSE2 enabled for better performance. For QML, SSE2 is required to make use of
the JIT. Those SSE2 enabled libraries are put into /usr/lib/sse2/*, but glibc
2.37 dropped the mechanism to look into this directory. As result, it always
used the binaries without SSE2.

Forcing the system to use the SSE2 enabled libQt5Qml.so.5 instead gets rid of
the crash, so it's likely that the SSE2 disabled build is just broken somehow.
Considering that support for this way of providing SSE2 enabled library
variants is no longer in glibc, I'll make SRs to drop support for systems
without SSE2 from libqt5-qtbase and libqt5-qtdeclarative.