Mambu should return the Mambu transaction ID when a duplicate deposit/withdrawal transaction is attempted to be posted through the API.
There are situations where an ATM posts a transaction to Mambu which is correctly logged in Mambu but the ATM then suffers from an internet outage when the confirmation is returned along with the transaction ID. The ATM will then receive a timeout and attempt to re-post the transaction resulting in the errorcode 148 being returned as the transaction is already posted. To keep the ATM and Mambu in sync we should at that point also return the Mambu transaction ID, e.g. to allow the reversal of the transaction at a later point (since the money was likely not disbursed by the ATM due to the timeout).
Related help article and errorcode:
|148 TRANSACTION_IDENTIFIER_ALREADY_USED||When the posted transaction identifier already been used (it exists in the data store)|