Good day, BethV.
Helping you move a line item on your invoice is my priority. Let's get this sorted out.
We haven't received similar issues reported. The behavior you've experienced is probably a browser-related issue. Cache and cookies make the browser easier and faster to use. However, too much of these may affect the browsing performance.
As an initial step, we can start with opening the QuickBooks account in a private browser.
If you're able to move a line item on your invoice using the private browser, let's go back to your regular browser and clear its cache.
You may find these articles helpful:
For account-related discussion, feel free to reach out to our QuickBooks Online Support.
If none of the steps work, try using a different browser. Please get back to me if you continue to get the same results so I can look further into this. Have a good one.