Why are transactions that I have categorised reappearing in my banking?

Hello there.

A possible reason bank transactions you've categorized in the past show in your For Review section inside your Banking page is that your bank account's refreshed, causing it to re-download your previous transactions. 

What you'll want to do is to Exclude them. This way, they won't appear on your banking page. You can also utilize the Filter option to filter the date to make it easy to determine old transactions and avoid excluding those recent bank transactions. I'll gladly write down the steps below to get you going. To begin, here's how:

1. Access your QuickBooks Online company.
2. On the left navigational bar, go to the Banking tab.
3. Choose the bank account, and then go to the For review section.
4. Click the All dates button.
5. Input the start date and end date to determine the period for those transactions that you'd like to exclude.
6. Click the Apply button.
7. Once done, click the box beside the Date section to select all the past transactions.
8. Click Exclude.

Now, after performing the steps I've provided, only the latest downloaded bank transactions will show in your For Review section inside the banking page. To manage your banking transactions, see this page: Categorise and match online bank transactions in QuickBooks Online.

Furthermore, I've got you this article to learn more about reconciling an account in QBO: Reconcile an account in QuickBooks Online.

It's been a pleasure to have you here today. Feel free to leave a comment below if you need help performing specific tasks inside QuickBooks. I'll be here, ready to assist you. Take care!