Comment # 22 on bug 1229721 from Franck Bui

(In reply to Stefan Seyfried from comment #21)
> My guess is still, the "handover" from initramfs to installed system (with a
> restart of journald?) is not working as intended and so for me the journald
> from initramfs is still running? But I have no real knowledge how this is
> supposed to work anyway, so I might be totally wrong here.

I think you're right:

systemd[1]: Switching root.
systemd[1]: systemd-journald.service: Releasing all stored fds
systemd[1]: Bus private-bus-connection: changing state CLOSING → CLOSED
systemd[1]: Failed to open pidfd for pid 2: Invalid argument
systemd[1]: Failed to enumerate /proc/: Invalid argument

In your case something wrong is happening when PID1 is supposed to kill all
remaining processes after switching root, which includes journald.

Can you try to figure out which process "pid 2" is ?

Maybe try to boot in emergency mode and check the content of /proc/2/comm for
that.