We have a consumer who is disputing transactions on their checking account and notified us on 8.16.2021. The initial transactions took place from July 2020 thru September 2020 which included both Debit and Credit Transactions. There are subsequent transactions which have taken place more recently. Are we only obligated to go back to review the disputes 60 Days before 8.16.2021?

No.

You have to look at the first transaction that the customer claims was not authorized, no matter how old it is. If you determine that it was not authorized, and that later transactions the customer is claiming were not authorized are related to that first unauthorized transaction:
1. Determine when you sent the customer the account statement showing the first transaction. If there isn't a lost or stolen card involved in the claim, add 60 days to that date, and consider that the coverage limit date. Let's assume it's 9/30/2020.

2. Any of the claimed transactions that you determine were unauthorized that posted on or before the coverage limit date (9/30) will be refunded to the customer.

3. Any of the claimed transactions that appear to be connected to those unauthorized transactions and that post after the coverage limit date (9/30//2020) may, in fact, be unauthorized, but the customer is responsible for them and you do not have to refund them. The customer failed to check statements and notify you of the unauthorized transactions, and you could have prevented them if you had been notified by that coverage limit date, so the customer is not entitled to a refund for them.

The problem is that you would have to apply section 1005.11 to transactions on the customer's list that are under 60 days old at the time. But if they are part of a series that started in July 2020, you only reimburse for the earliest unauthorized transactions.

Are the claims for remittance transfers charged to the customer's account or are they ATM, debit card or ACH debits?

Yes they area charged to the account and there are ATM Credits, POS Debits, POS Credits, and ACH Debits.

Then they don't appear to be remittance transfers under subpart B of Reg E, so I am relocating this discussion to the Deposits and Payments forum.