In a Quest List Form you can save a form without filling out all required fields. For example, If you create a new contact, default values in the required field are being perceived as filled out. In addition, if a required field is left blank, the form still allows the user to save without entering the data.
TitleQuest List Form – You can save a form without filling out all required fields
Waiting for a fix in a future release of Development Studio for SharePoint.