If it allow for the using both MyInvoice Portal and API for submission of e-Invoice, can IRBM’s system detect duplication of submission? (e.g. 1 via MyInvoiceQ Portal, 1 via API)

Supplier is allowed to use both submission mechanisms (i.e. API with MyInvois Portal), however, as mentioned in the e-Invoice Guideline, it is the responsibility of the Supplier to ensure no duplication in the invoice submitted.  This means IRBM’s system will not detect duplication of Invoice.