Foreman "Some Puppet Classes are unavailable in the selected environment"

Problem:
a hostgroup that has been working with a base set of puppet modules associated with it somewhere in the 3.2 cycle suddenly started giving a missing puppet warning (probably triggered by adding / removing a module) against that hostgroup, but there isn’t actually any missing module, this has continued into a foreman 3.3.0 upgrade.

Expected outcome:
no warnings or errors

Foreman and Proxy versions:

Foreman and Proxy plugin versions:
3.3.0

Distribution and version:
CentOS 8 Stream

Other relevant data:
puppet run doesn’t fail or complete any errors, I suspect there has been some confusion with an addition/removal of a puppet module during normal usage. I’m not sure what data is generating the warning of a missing module (normally you would see a red X against the missing module)

while it’s not causing any actual problems I’d like to understand what’s causing it and clean it up, I don’t believe this is a bug

It helps to first search for topics on the same issue.

See Some Puppet Classes are unavailable in the selected environment

and Bug #34402: Hostgroup error: Some Puppet Classes are unavailable in the selected environment - Puppet - Foreman