KDP Edit button broken until mix loaded

If a mix being displayed in the KDP allows editing, but the mix has not fully loaded, it's possible to click the Edit button and get an error from KAE that the entry ID is null. Once the mix is fully loaded, the Edit button works fine. This is obviously problematic for larger projects, as editors often get this error if they open the page and click the Edit button quickly. A more desirable behavior would be to have the Edit button greyed out until it has an entry ID to work with.