blank set_value() return default value

Code:

set_value('user[name]', $user->name);

On use this code im my input, the input value is set to default ($user->name) when loaded.
By replacing the default value with a blank value and send the form, the input is displayed with the default value with the form error 'required'.

I want the value, even blank, is setted after sending the form.
I'm using codeigniter 3, if i remember, this did not occur in 2.

Thanks.

I'm having the same problem in v3.0.1-dev.