Here is how to reproduce the bug:
Create an editable grid form with two select fields (both with lookup method automatic via sql).
On the first field create an event on change using AJAX to reload the second fields of type Select.
Insert three records using the form and then try to update the first or the second record.
- You will get an invalid data message whenever you try to update any record but the last one.
- You will get an invalid data message whenever you try to delete any record but the last one.