Hi Mike,
I just checked my MYOB and the duplicated transactions are still there.
Further info for your team. We have moved all the duplicated transactions to "hidden" so we can continue managing the Bank accounts daily, but the duplicates are still visible in the account reconcile screen. Also, all the business reports (cash flow, P & L, Aged creditors, Sales, GST accruals) are a mess and we (all Australian customers) are required to reconcile and pay IAS and GST tax contributions by next week and require these reports to have accuracy - ATO won't accept "Dog ate my accounting software".
I hope your team are working over the weekend, as this is critical.