Has anybody had random invoice details copied into an invoice on post

We have a customer that has had invoice lines copied over from unrelated invoices when posting a new invoice using the SDK. I've confirmed that the data was copied from an invoice already in Sage as the data that was added included unique serial numbers were in the other invoice and did not exist in the source system.

We use the Sage 50 CA SDK to post an invoice with no unusual code, just posting the invoice in the prescribed manor but these details seem to come along for the ride somehow.

I don't know if this is the result of a database corruption or multiple users using the system at the same time or something else. 

Has anyone else seen this happen?