Cannot add a category that has the same name as a blog post

Steps to follow to reproduce:

• Create a new blog post named "test" and save it
• In edit mode click on "Add a category"
• Write test in the "New category" field
• Click "Add"

You will get the following message: "Target document already exists, please choose a different name"

You cannot add a category that has the same name as a blog post.