Redirects to index instead of new URL after validation failure on create, is that right?

[J]

After submitting to the create action from the model/new page, if
there are validation errors the template from the new page is
rendered, but the URL changes to the index page.

For example with the Agility application:

1) Goto the New Project form: http://127.0.0.1:9943/users/1-admin/projects/new

2) Try and create a project with a blank Name

3) You will be redirected to a page with the New Project form with the
validation error messages/highlighting, but the URL in the address bar
is http://127.0.0.1:9943/users/1-admin/projects (note: no "/new" at
the end)

Seems like we'd want the URL to stay at /new, is this a Hobo bug or is
there some intentional reason for this behavior?