With the latest change to pambase, e.g.
if you have services that rely on pam authentication, such as dovecot, etc.., you will find that your applications an no longer authenticate using pam until you install a specific pam service in /etc/pam.d for that application, e.g.
I recall seeing something about this change coming earlier, but this was the first update where something stopped working as a result. So add whatever additional files you require to /etc/pam.d/
Thankfully the journal messages are good in pointing out the problem.