If I create a report and download as a csv the custom fields show up in the Invoices section, but in Sales Orders they are blank.

Similarly, if I do an API call on records I can get an array with the custom fields from invoices, but from sales orders I just get empty fields for cf_1, cf_2 and cf_3.

I need to use the information in these fields in my Sales Order reports to customers, so can you tell me why I can't see them anywhere?

Thanks.