I operate many PSBM (Paralells Server for Bare Metall) nodes. This is a patched CentOS 6 based operating system from parallels. The facts are a bit different to a normal CentOS 6 machine. You can see an example here: https://github.com/theforeman/puppet-puppet/pull/487

I get a long error when I try to submit the facts to foreman:

2017-03-11 11:49:38 df26fb2c [app] [W] Action failed 
 | ActiveRecord::RecordInvalid: Validation failed: Minor version is not a number
...
2017-03-11 11:49:38 df26fb2c [app] [I]   Rendered api/v2/errors/standard_error.json.rabl within api/v2/layouts/error_layout (0.6ms) 
2017-03-11 11:49:38 df26fb2c [app] [I] Completed 500 Internal Server Error in 909ms (Views: 1.5ms | ActiveRecord: 354.1ms)

The facts are available here:
https://gist.github.com/bastelfreak/2c396428e3435aec77bb8bf998a16bb7#file-gistfile1-txt-L98

I had to trim some sensitive information, but I guess the os hash is the important one. I'm running the latest foreman on CentOS 7:

~ # rpm -qa | grep foreman
tfm-rubygem-foreman_hooks-0.3.13-1.fm1_14.el7.noarch
tfm-rubygem-foreman_column_view-0.3.0-1.fm1_14.el7.noarch
foreman-release-scl-3-1.el7.noarch
tfm-rubygem-foreman-tasks-core-0.1.1-1.fm1_14.el7.noarch
foreman-selinux-1.14.2-1.el7.noarch
foreman-1.14.2-1.el7.noarch
tfm-rubygem-puppetdb_foreman-2.0.0-1.fm1_14.el7.noarch
tfm-rubygem-foreman-tasks-0.8.6-1.fm1_14.el7.noarch
foreman-postgresql-1.14.2-1.el7.noarch
foreman-debug-1.14.2-1.el7.noarch
foreman-proxy-1.14.2-1.el7.noarch
~ #

And the packages on my puppetserver/foreman-proxy node:

~ # rpm -qa | grep foreman
foreman-postgresql-1.14.2-1.el7.noarch
tfm-rubygem-foreman-tasks-0.8.6-1.fm1_14.el7.noarch
tfm-rubygem-foreman_hooks-0.3.13-1.fm1_14.el7.noarch
tfm-rubygem-foreman-tasks-core-0.1.1-1.fm1_14.el7.noarch
foreman-selinux-1.14.2-1.el7.noarch
tfm-rubygem-puppetdb_foreman-2.0.0-1.fm1_14.el7.noarch
foreman-debug-1.14.2-1.el7.noarch
foreman-1.14.2-1.el7.noarch
foreman-proxy-selinux-1.14.2-1.el7.noarch
tfm-rubygem-foreman_column_view-0.3.0-1.fm1_14.el7.noarch
foreman-release-scl-3-1.el7.noarch
foreman-proxy-1.14.2-1.el7.noarch

I digged through my logs. I started with foreman 1.14.0. This bug was already present in that release and all upcoming. Let me know if you need any additional information