Hi there, LF8.
Since you're accessing Banking from the left menu, I believe you're using QuickBooks Online. The provided steps above are for QuickBooks Desktop. I suggest going to the Accounting section. From there, you can delete the duplicate bank transfer from your register.
1. Click Accounting at the left panel.
2. Choose Charts of Accounts.
3. Find the bank.
3. Click the View register under Action column.
4. Find the duplicate bank transfer and click it to expand the page.
5. Hit the Delete button.
For additional information how recording a funds transfer between two accounts works in QBO, you can refer to this article: Transfer funds between accounts.
If you want to move money from one company to another, please check this article on how to perform the steps: Transfer funds between companies.
Please let me know if you have other questions related with QuickBooks. I'm always here to help you.