Changes in /etc/pam.d/system-auth present in the 20200721.1-2.nonsystemd1 package for pambase causes 'Module is unknown' errors from all tools and services authenticating via it, as it attempts to invoke pam_faillock.so, which _does not exist_ in the most recent pam version for 32 bit (still at 1.3.1-1.3 – whereas pam_faillock was introduced in 1.4.0.)

e.g:
<pre>
- sudo[29894]: martin : PAM authentication error: Module is unknown ; TTY=pts/9 ; PWD=/home/martin ; USER=root ; COMMAND=/usr/bin/pwd
- dovecot[21651]: auth-worker(21713): pam(martin,192.168.2.1,
<Rup9NYutxLTAqAIB>): pam_authenticate() failed: Module is unknown
</pre> <pre>

This is quite serious; as it prevents anyone from authenticating to the system once the pam.d changes are in place. Please ensure that the corresponding pam package is upgraded at the same time or even *before* introducing system-breaking changes such as this.