Why did AutoInvoice create transactions with duplicate transaction numbers?

During AutoInvoice processing, the import process validates that transaction and document numbers are unique after grouping has completed.

In certain cases, AutoInvoice will create multiple invoices in the same group with the same transaction or document number. Once grouping is completed, AutoInvoice checks for duplicate transaction and document numbers and reports any lines that fail validation.

For example, two lines are imported with the same transaction number, but they have different currencies. These lines are split into two separate invoices during grouping due to the different currencies. Once grouping has completed, both of the invoices will fail validation due to identical transaction numbers.