Hi,
@lzap has explained the logging behaviour here in another toppic. From what I understand, not being able to configure the rails logs is originally an issue with ruby on rails and not Foreman itself.
Yet, the logs you are sharing point to an underlying problem that should be fixed, not just filtered away with different log settings (stack traces are usually bad 
). Can you correlate these messages to certain actions, like creating a new host, puppet runs, etc.?
I am not a dev, but from what I see in the logs, it looks like foreman recieves invalid IPv6 addresses from Puppet facts and fails upon importing/saving those.
Edit: Corrected lzap’s name