This is a known issue in Chrome to do with browser session data. It should resolve itself in time but incognito mode can be used to bypass it on a temporary basis or consider trying these steps:
- Press F12 to open the Developer Tools when on the page
- Navigate to the application tab in the Developer Tools panel
- Click on Storage from the left hand menu. It is under 'Application'.
- Click the "Clear Site Data" button
- Refresh, log back in
- Observe able to edit.
In my case I used CCleaner to remove temporary files after Step 4 and rebooted the PC.