In Qgis 2.2 I had a form with tabs. In each tab I repeated the same attribute at the top along with other attributes that did not repeat. When I updated the attribute which repeated on each tab the same attribute would update on each tab. In 2.4, when I update the repeating attribute on one tab it does not repeat the update on other tabs and will not save the change unless all repeating attributes have the same value.
Please file a bug. Before 2.2 it worked only for certain edit types and
was quite a hack to have it working for these.
With the new widget system it should be easy to implement the same
behavior for (almost?) all widget types.