On my Centos 7 update, into "journalctl -f" I have tons of this kind of message

feb 17 23:52:09 s-ispc.local systemd-logind[663]: Got message type=signal sender=:1.0 destination=n/a object=/org/freedesktop/systemd1/unit/php_2dfpm_2eservice interface=org.freedesktop.DBus.Properties member=PropertiesChanged cookie=17152 reply_cookie=0 error=n/a feb 17 23:52:09 s-ispc.local systemd-logind[663]: Got message type=signal sender=:1.0 destination=n/a object=/org/freedesktop/systemd1/unit/php_2dfpm_2eservice interface=org.freedesktop.DBus.Properties member=PropertiesChanged cookie=17153 reply_cookie=0 error=n/a feb 17 23:52:11 s-ispc.local systemd-logind[663]: Got message type=signal sender=:1.0 destination=n/a object=/org/freedesktop/systemd1/unit/httpd_2eservice interface=org.freedesktop.DBus.Properties member=PropertiesChanged cookie=17154 reply_cookie=0 error=n/a feb 17 23:52:11 s-ispc.local systemd-logind[663]: Got message type=signal sender=:1.0 destination=n/a object=/org/freedesktop/systemd1/unit/httpd_2eservice interface=org.freedesktop.DBus.Properties member=PropertiesChanged cookie=17155 reply_cookie=0 error=n/a

And into /var/log/messages I have this warning message:

rsyslogd-2177: imjournal: begin to drop messages due to rate-limiting

What is happening?

It is possible to stop this message?

Many thanks