My bank is showing a deposit that I did not make (to confirm) when I updated....how do I fix that?

Welcome to Community, fnms.

Allow me to share with you the steps on how to undo deposit in QuickBooks Online.

You'll need to delete the deposit from your bank account register to keep your financial data accurate. To do this, here's how:

1. Go to Accounting and choose Chart of Accounts.
2. Select your bank account.
3. Under ACTION, select View Register.
4. Locate the deposit.
5. Select Delete.
6. Click Yes to confirm.

Also, I'm adding this article for helpful ideas about managing your account and related transactions: Reports and Accounting for QuickBooks Online.

Keep me posted if you have other concerns about managing your deposits and other banking transactions in QBO. I'm just around to help. Take care, and wishing you continued success.