MariaDB(.org) packages on Systemd have the following option in the unit service file:

ExecStartPost=/bin/sh -c "systemctl unset-environment _WSREP_START_POSITION"

What can happen is that MariaDB is started but not yet accepting connections(for example due to some internal maintenance) so any tool that relies on the information provided by Systemd whether MariaDB is started or not to do some operation (think of containers or any automation tool) can fail because of this.

CentOS/RHEL packages have:
ExecStartPost=mariadb-wait-ready

The mariadb-wait-ready script does a mysqladmin ping basically.

Would it be better to declare started MariaDB only when already accepting connection?