I've create a basic canvas phone app through the wizard using a CDS Entity for the data source. When I edit a selected record through the EditForm, if I clear a field that has text in it and then submit the form, the system throws an error message "An entry is required or has an invalid value" for the field I cleared. This happens in multiple text input fields I have tested. These fields are not defined as required fields in CDS. I would think I could clear the data in one of these fields and submit the record change. It seems to act as though once the record is saved with a value in one of these text input fields that it requires a value in it going forward.
Can someone please explain to me why this is happening and what I can do about it? Thanks for any help or ideas.