The documentation for the Company Officer list resource https://developer.companieshouse.gov.uk/api/docs/company/company_number/officers/officerList-resource.html does not have "Optional." listed in the additional details for the field "appointed_on". It was my understanding that this meant that the field was mandatory, yet for some company's officer lists, some of the officers to not have an "appointed_on" date.
I'm unsure whether this is a data issue i.e. the documentation is correct but that the data is missing for some officers. Or if it is just that it really is an optional field and the documentation is incorrect?