Almost any time PID 1 segfaults, it's PID 1's fault. With PID 1 being systemd, that makes it systemd's fault here. Based on gdb stack backtraces in the Fedora bug report and looking at the systemd code, it seems like some sort of memory corruption or overwrite, perhaps a use after free issue. The segfault itself comes from dereferencing a clearly invalid pointer and said pointer was obtained by dereferencing a structure field through another pointer, so you'd get exactly this result if the structure was overwritten with other data at some point.

(In my grumpy sysadmin view, it is PID 1's fault even if the distribution is doing odd things around PID 1. Init processes need to be absolutely rock solid and extremely defensively coded, precisely because the world basically dies if they ever fall over.)

(I am the author of the original post.)