Auto reversal program launching for reporting currency

We have created a a global responsibility for GL with access (through data access set) to 2 primary ledgers in Italy, 1 Primary Ledger in the US and 1 reporting unit in the US. The conversion level of the reporting ledger is 'Journal'.

We ran 'Open Period' program for the ledger set and it spawned 4 autoreversal programs for the four ledgers. However, the one fired for the reporting currency ended with error. What we found is the autoreversal progam that was fired for the US ledger actually generated all the reversals for both the primary ledger and the reporting currency. The questuion is if the autoreversal program for the primary ledger will create all the reversals in both the promary and reporting currency, then why does the autoreversal program is fired for the reporting currency? This program for reporting currency is not