Thank you for providing us more information about your concern, kingcohandymanse.
QuickBooks Online is basically dependent on what your bank shares with us. Thus, we have no control of the exact transactions that can or cannot be downloaded within the Banking page.
Based on the details you've given, we are dealing with a parent-child accounts in the Banking page. With that setup, we can't connect both parent and subaccounts. We can only recommend to create two subaccounts where the bank transactions flow separately. You can check this article to see the details: About bank or credit card subaccount setup.
If you have followed the setup and still got the same problem, I'd recommend contacting your financial institution. They can give you further instructions on how to get through with this. You can also view this link if you encountered bank error within the Banking page: What to do if you get a bank error or can't download transactions in QuickBooks Online.
Lastly, you can reach out to our support if you get a confirmation from your bank that everything is working fine on their end. Our support will be able to review your situation further.
Though you are already familiar with the importing process, I'll just share these links for your reference wherefore:
Keep in touch with us so we'll be updated of your situation until its settled. We'll be here for you!
