I setup a feature service with non-nullable field and have setup the app to make the field required*.
I was running into the same issue of empty strings as default values and ran this script so that users had to actually fill out every field.
As I was testing, I finally got the expected behavior on my iOS device. However, I have partner groups who are using Field Maps on Android. Now, I have run into a new issue, where users can submit a new feature without filling out required fields. Rather than throwing an error that a field is required, android field maps is submitting the new feature with null values, effectively creating an invalid feature. Upon submission, the field maps user's polygon disappears and ALL fields are shown as null and arcade expressions are displaying as NaN. As far as I can tell, the new features are never actually submitted to the service and the data seems to just vanish on the device as well.
Is this just an android release bug?
All I'd like to do is make a field on a form required to be filled and thought I'd jumped through all the hoops to do so.