AP Invoice Lines - intermittent Transaction Business Category is empty

Summary:

When creating / editing invoices, the AP Invoice Line's Transaction Business Category field is empty sometimes.

Content (required):

When creating invoices (from a variety of sources, including Manual Invoice Entry), the following is happening on a random basis:

1. Create new AP Invoice
2. Populate Invoice Header
3. Click "Match Invoice Lines" on Lines section
4. Search for PO, select PO in search results, populate Amount and click OK
5. On new Invoice Line, Transaction Business Category is empty.

While it can be populated again, if a user forgets to do that, it can cause issues for Tax Reporting, as Tax Box Allocation processes contain rules which check the value of this field.