Your default must be different to Raspbian default then.
From the man on my system;
CONFIGURATION DIRECTORIES AND PRECEDENCE
The default configuration is defined during compilation, so a configuration file is only needed when it is necessary to
deviate from those defaults. By default, the configuration file in /etc/systemd/ contains commented out entries showing the
defaults as a guide to the administrator. This file can be edited to create local overrides.
The commented out settings are what was set to default when the package was compiled. journald.conf(5) — systemd — Debian testing — Debian Manpages
pi@emonpi:/var/log $ cat /etc/systemd/journald.conf
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See journald.conf(5) for details.
[Journal]
#Storage=auto
#Compress=yes
#Seal=yes
#SplitMode=uid
#SyncIntervalSec=5m
#RateLimitIntervalSec=30s
#RateLimitBurst=1000
#SystemMaxUse=
#SystemKeepFree=
#SystemMaxFileSize=
#SystemMaxFiles=100
#RuntimeMaxUse=
#RuntimeKeepFree=
#RuntimeMaxFileSize=
#RuntimeMaxFiles=100
#MaxRetentionSec=
#MaxFileSec=1month
#ForwardToSyslog=yes
#ForwardToKMsg=no
#ForwardToConsole=no
#ForwardToWall=yes
#TTYPath=/dev/console
#MaxLevelStore=debug
#MaxLevelSyslog=debug
#MaxLevelKMsg=notice
#MaxLevelConsole=info
#MaxLevelWall=emerg
No, we are not.
On the EmonSD there is no folder /var/log/journal, and the Storage= is set to auto so logs are only held, by journald in RAM not on disk. auto will create a /run/log/journal/ folder if it does not exist but will not create a /var/log/journal folder. So the user needs to choose to hold the journal on disk either by changing the storage= to persistant or create the /var/log/journal folder.