I'd like to share some information about the old deposits showing up when reconciling in QuickBooks Online.
To get rid of the old deposits, you'll need to include these records when reconciling your account in QuickBooks Online. The system wanted to make sure that there no transactions left.
If you don't want to include these old deposits, you can simply delete them. However, doing so will affect your QuickBooks Balance. I'd suggest working with your accountant so they can provide more expert advice regarding an accounting perspective.
For the detailed steps about this process, you can read through this article: Reconcile an account in QuickBooks Online. On the same link, you'll find write-ups about how to review your previous reconciliation as well as adjusting them in QuickBooks.
If you still need help with the reconciliation process, please let me know. I want to make sure your concern is fully addressed and I'm here to provide further assistance whenever you need it. Have a great rest of the week!