If you register a payment of an open invoice than you will be ask for which (bank) journal you want to register this payment. The sence here should be that the journal item only appears in the bank statement of this journal when you do reconciliation. This will fasten the process of reconciliation espacially if you have many open lines. 

It doesn`t make any difference in which bank statement you try to reconcile. Every time all open invoices appears when try to reconcile. This is a massive performance issue because odoo is loading all open journal items instead of only the invoices that had been set to this journal.

The behavior should be like this: Only the journal items that had been set with the journal should be appear in the bank journnal when reconcile.

Any help from Forum?