So you're trying to update the starting balance on your fund item or debt item. But you get a message that says "No jumping ahead! You can only update the balance for the current month." For now the only way to update this balance is during the current calendar month. So if it's September 28th and you want to update October's balance, you'll need to wait until October 1st to make that change.
We realize this is not ideal and this is something our team would like to address in the future. Thanks for your understanding.