Unknown error

Problem:
2022-07-06 09:38:19 [DEBUG ] [configure] Found key: “foreman::cli::ssl_ca_file” value: nil
2022-07-06 09:38:19 [DEBUG ] [configure] Scope(Class[Foreman::Cli]): Retrieving epp template foreman/hammer_etc.yml.epp
2022-07-06 09:38:19 [DEBUG ] [configure] Scope(Class[Foreman::Cli]): Retrieving epp template foreman/hammer_root.yml.epp
2022-07-06 09:38:19 [DEBUG ] [configure] importing ‘/usr/share/foreman-installer/modules/foreman/manifests/cli/plugin.pp’ in environment production
2022-07-06 09:38:19 [DEBUG ] [configure] Automatically imported foreman::cli::plugin from foreman/cli/plugin into production
2022-07-06 09:38:19 [DEBUG ] [configure] importing ‘/usr/share/foreman-installer/modules/foreman/manifests/plugin/tasks.pp’ in environment production
2022-07-06 09:38:19 [DEBUG ] [configure] Automatically imported foreman::plugin::tasks from foreman/plugin/tasks into production
2022-07-06 09:38:19 [DEBUG ] [configure] importing ‘/usr/share/foreman-installer/modules/foreman/manifests/params.pp’ in environment production
2022-07-06 09:38:19 [DEBUG ] [configure] Automatically imported foreman::params from foreman/params into production
2022-07-06 09:38:19 [DEBUG ] [configure] Unknown variable: ‘foreman::params::plugin_prefix’. (file: /usr/share/foreman-installer/modules/foreman/manifests/plugin/tasks.pp, line: 18, column: 16)
2022-07-06 09:38:19 [ERROR ] [configure] Evaluation Error: Error while evaluating a Method call, ‘regsubst’ parameter ‘target’ expects a value of type Array or String, got Undef (file: /usr/share/foreman-installer/modules/foreman/manifests/plugin/tasks.pp, line: 18, column: 56) on node otvmi344s.priv.atos.fr
2022-07-06 09:38:19 [DEBUG ] [configure] Found in cache :production (ttl = 0 sec)
2022-07-06 09:38:19 [NOTICE] [configure] System configuration has finished.
2022-07-06 09:38:19 [INFO ] [post] Executing hooks in group post
2022-07-06 09:38:19 [DEBUG ] [post] Hook /usr/share/foreman-installer/hooks/post/30-upgrade.rb returned nil
2022-07-06 09:38:19 [DEBUG ] [post] Hook /usr/share/foreman-installer/hooks/post/34-pulpcore_directory_layout.rb returned nil

There were errors detected during install.
Please address the errors and re-run the installer to ensure the system is properly configured.
Failing to do so is likely to result in broken functionality.

The full log is at /var/log/foreman-installer/foreman.log
2022-07-06 09:38:19 [DEBUG ] [post] Hook /usr/share/foreman-installer/hooks/post/99-post_install_message.rb returned nil
2022-07-06 09:38:19 [DEBUG ] [post] Hook /usr/share/foreman-installer/hooks/post/99-version_locking.rb returned nil
2022-07-06 09:38:19 [INFO ] [post] All hooks in group post finished
2022-07-06 09:38:19 [DEBUG ] [root] Exit with status code: 1 (signal was 1)
2022-07-06 09:38:19 [DEBUG ] [root] Cleaning /tmp/kafo_installation20220706-115928-1wn3p9e
2022-07-06 09:38:19 [DEBUG ] [root] Cleaning /tmp/kafo_installation20220706-115928-1j41abl
2022-07-06 09:38:19 [DEBUG ] [root] Cleaning /tmp/default_values.yaml
2022-07-06 09:38:19 [DEBUG ] [root] Installer finished in 6.508942841 seconds

Expected outcome:
a working config !

Foreman and Proxy versions:
3.3.0-rc2

Distribution and version:
rhel8
Other relevant data:
command was :
foreman-installer -l DEBUG --enable-foreman-proxy-plugin-discovery

I had this error with 3.2.1 with a similar command line. Apparently, my answers file got clobbered during an upgrade, and so I had to re-run the installer with all of the installation arguments to get it to run correctly.