This has been a MAJOR BUG for many many months now.
There is definitely an error in the Form.Unsaved Property.
I have many occasions where I have changed the Update property of a DataCard, or the Default property of a Card Control - but as long as the Values are the same, then it should validate OK, and NOT set the Unsaved property to true.
Sometimes, this works, and sometimes not, and the really unfortunate thing is that I have not yet found any pattern as to when it works OK and when it doesn't.
(I use SharePoint Lists as a DataSource, but I don't use SharePoint Lookup fields, and prefer to make my own relationships using ForeignKeyID number fields instead. I have also ruled out the old problem with Date fields where it tries to compare the existing value with the "InputTextPlaceholder" property)
Currently, I have to resort to writing very lengthy validation formulas that compares every field on the form with the value currently saved in the SharePoint List, but as some of my more complicated Forms include 50+ fields, these are ungainly and prone to errors or omissions, and kind of makes me question how useful the Form controls are in the first place...
Can someone from Microsoft please update us on when this bug in the Form-Unsaved is going to be fixed?
Thanks
James.