Preconditions:

Article created in Home

Steps to reproduce:

1. Go to Article
2. Go to "URL" tab
3. Click the button
4. Enter URL and disable the "Place alias at the site root" checkbox.
5. Click Create
6. Click the button again
7. Enter URL
8. Click Create

Actual result:

Both URL aliases looks the same /alias_name

Expected result:

The checkbox "Place alias at the site root" should be disabled, because unchecked it creates the new alias under Home, so no matter if (un)checked it will always look the same