No stack trace in production log

UPDATE2: It looks like I’m seeing stack trace when I run my release directly with <my_app> start.
However when I run same release as systemd service I no longer see error stack trace.

Here is my systemd config:

[Unit]
Description=Phoenix Codercat Server
After=network.target

[Service]
Environment=MIX_ENV=prod
Environment=PHX_SERVER=true
Environment=DATABASE_URL=xxx
Environment=SECRET_KEY_BASE=xxx
WorkingDirectory=/home/kiko/phx-codercat
Type=simple
Restart=always
RestartSec=1
User=kiko
ExecStart=/home/kiko/phx-codercat/bin/codercat start
ExecStop=/home/kiko/phx-codercat/bin/codercat stop
ExecReload=/home/kiko/phx-codercat/bin/codercat restart

[Install]
WantedBy=multi-user.target

And to see logs I use journalctl -uf <service_name>

I reviews the following relevant post here.