17 June 2026
When the invoice posts twice and the dashboard still looks clean
A duplicated e-Invoice submission does not always announce itself. Here is how we trace a double posting through a Malaysian automation stack.
A controller in Penang asked us to look at a sales-tax control account that had grown by a few thousand ringgit each month without a matching rise in turnover. The application’s home screen showed invoices ‘sent’ and a green reconciliation badge on the bank feed. Nothing looked urgent.
The duplicate lived in a workflow that created the invoice in the billing module, pushed it to MyInvois, then posted a second time when a webhook retried after a timeout. The second journal used a slightly different document number suffix, so the uniqueness check never fired.
We now ask three questions on every posting-rule audit: does the application treat the tax authority acknowledgement as the posting trigger, or the save button? What happens on retry? And can a user void one journal without voiding the e-Invoice?
If your tax control account is drifting while revenue looks stable, export the journal source codes for a single month and sort by amount. Pairs that differ only by a suffix are worth a morning of someone’s time before they become a year-end conversation.