When adding to a basket from a staged file, we populate item information on the main tab if using MarcItemFieldsToOrder, however, upon submission we can get an error: "Some required item subfields are not set" This is because the second tab 'Item information' uses the standard item editing form, and checks that all required fields are filled. These inputs are ignored when item information is present on the other tab. We should not build this form when using MarcItemFieldsToOrder See bug 20473
It looks like there is another bug asking for the item information to be taken into account, but I agree that removing it would make it less confusing for now: Bug 22108 - Items generated through MARCItemFieldsToOrder do not receive values applied in Item Information and Default Accounting Details
New Koha library experiencing this same issue when staging carts from Baker & Taylor. We'd love to see a fix!