auditctl complains with "There was an error in line 2 of /etc/audit/audit.rules" and no rule gets loaded

Issue

• When starting the auditd service, the following auditctl message is seen in the journal and no rule gets loaded

  [...] auditctl[XXX]: There was an error in line 2 of /etc/audit/audit.rules
  

• Content of /etc/audit/audit.rules file looks correct, e.g.

  ## This file is automatically generated from /etc/audit/rules.d
  -D
  [...]
  

  or when the rule file is something customized (content may vary)

  # Do not edit any of these rules directly. The contents of this file are
  # controlled by an automation tool