Fedora Media Writer flatpak build often crashes in HTTP header decoding in Fedora openQA testing

We have a test in Fedora openQA which boots the Fedora Silverblue (atomic GNOME) image, and tries to run every preinstalled application. One of those preinstalled applications is Fedora Media Writer (the Fedora flatpak build of it), which is based on Qt. Quite often, when run by this test, it crashes before the UI appears. The backtrace runs through Qt HTTP header decoding and ends with `error reading variable: Cannot access memory at address 0x2` (full backtrace is attached).

The earliest case of this I can find happened on February 13th, on Fedora 42. The first case on Rawhide happened on Feb 15th. Since then, almost every run on Rawhide has failed this way, and more than half the runs on F42.

I run F42 Silverblue myself, and have tried running FMW several times in a row on my local system, but it worked fine every time with that test. I'm not sure if this bug maybe only happens on the first attempt and I got lucky, or there's a timing issue, or what.