If you voided checks in a different month than they were created, the bank account and cash account will remain out of balance until the reversals post to the cash account. If you must correct this in the current period, you can create an automatically reversing journal entry to your GL cash account. Otherwise, you can leave the transactions as outstanding until the month they were voided in.

For help on finding all payments that were created in one fiscal period and voided in another refer to Article 39785.