At the moment, a Posted Field that is Two Option will override the field to which it is mapped if the original value of the mapped field is null -- EVEN IF OVERRIDE IS SET TO NO.
I thought this was a bug, but was informed by support that this was the expected behavior.
I was wondering why this is the case. If a Form Field is set to Override = no, it would be expected that the Posted Field will never, in any circumstance, push directly to the mapped field. Why is a null field an exception, and how are your end users to know this unless they go through every minor detail of the documentation? No means no. No does not mean 'sometimes' or 'in certain circumstances'.
I do understand that if someone were to visit the Form and submit it with the field unchanged, that it is no longer null and is now false/no/off. I don't see why this necessitates an override of the mapped field. I have workflows to handle the updates to the mapped field based on the comparison of the new value from the Posted Field to the old value on the Contact record - isn't that part of the reason why the override feature is available to begin with - so that we can set our own behavior based on the response?
With the current setup, if I want to create a new field and send it out to my Contacts to be updated, I need to pre-populate the field for over 100,000 Contact records first.
(this was tricky to explain, so let me know if clarification or more detail is required)