https://theforeman.org/api/1.22/apidoc/v2/architectures/index.html (and all other Foreman objects) says:

page (optional) paginate results
Validations: Must be a String

per_page (optional) number of entries per request
Validations: Must be a String

If you compare this to Katello (https://theforeman.org/plugins/katello/3.12/api/apidoc/v2/activation_keys/index.html), you see:

page (optional) Page number, starting at 1
Validations: Must be a number.

per_page (optional) Number of results per page to return
Validations: Must be a number.

This is IMHO both more logical from the wording and the validations.

The problem with the Foreman approach is that if an API client actually looks at "expected_type" (which is "string" in Foreman and "numeric" in Katello), it will refuse to pass integers to the API.