Comment # 7 on bug 915575 from Thomas Blume

(In reply to Tom���� Chv��tal from comment #6)
> Created attachment 621583 [details]
> systemd debug logging

Hm, I don't really see a bug.
There are 2 times signals sent to journald.
The first time it seems to be caused by the switch from initrd to real system
root: 

-->--
[    5.084442] BTRFS info (device sda3): disk space caching is enabled
[    5.099132] BTRFS: detected SSD devices, enabling SSD mode
[    5.293630] systemd-journald[184]: Received SIGTERM from PID 1 (systemd).
[    5.491167] BTRFS info (device sda3): disk space caching is enabled
--<--

Is sda3 your system root?
If so, this SIGTERM is normal. After switch root the journal is restarted on
the real root device.

The other signal I can see is a trigger for a journal flush (see man
systemd-journald.service > SIGNALS for reference): 

-->--
About to execute: /usr/bin/systemctl kill --kill-who=main --signal=SIGUSR1
systemd-journald.service
Forked /usr/bin/systemctl as 474
systemd-journal-flush.service changed dead -> start
--<--

This indicates that journald was correctly started before.
What shows:

systemctl status journald

in the running system?