Comment # 28 on bug 954139 from Marcus Meissner

systemd src/login/sd-loginc.c:

_public_ int sd_session_is_active(const char *session) {


        r = parse_env_file(p, NEWLINE, "ACTIVE", &s, NULL);

        r = parse_boolean(s);

explains this ;)

But I see the systemd issue from your comment #c26.