Class field validation does not work when enabling form validation

Steps to reproduce:
1. Create a class 'MySpace.MyClass' with a property of type String called 'phone'
2. Set its validation regular expression to /^[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]$/ (that would match 000-000-0000)
3. Add a validation message for this field
4. Create a sheet and bind it to this class, containig :

{{velocity}}
#set($myObj = $doc.getObject('MySpace.MyClass'))
; Phone
: $doc.display('phone', $myObj)

#if($xcontext.action == 'edit')
  {{html}}
    <input type="hidden" name="xvalidate" value="1" />
  {{/html}}
#end
{{/velocity}}

5. Create a template document 'MySpace.MyTemplate' and add an object of type 'MySpace.MyClass'
6. Create a new document going to : http://localhost:8080/xwiki/bin/edit/MyOtherSpace/TestPage?editor=inline&template=MySpace.MyTemplate
7. Fill in the 'Phone' input with 'a' (a value that would not pass the validation)
8. Click on 'Save & View' button
9. You will notice that the form fields are readonly and a notification saying 'Saving ...0%' is displayed at the bottom of the page, then nothing else happens (see the screenshot)

Expected result : the user would be redirected to the preview action, allowing her to modify the field value and the validation error message could be nicely displayed in the form.