When a user attempts to save a data form that has been extended to add additional fields and make fields required the error ' Data could not be saved. The record being updated has been changed by another user' occurs.
The issue appears to be related to concurrency. That is, the TSLONG loaded in the form LoadImplementation is the TSLONG from the dbo.INTERACTION table which is the same table (and record) that the extension is updating. Changing the TSLONG in the LoadImplementation to either a 0 or a value from a related\different table allows the record to save successfully.