List with Bindable SharedObject dataProvider ... bind fails

I have a bindable sharedObject that stores an offline ArrayCollection.

My List's dataProvider is bound to this offline ArrayCollection.

<s:List dataProvider="{offlineSO.data.myAC}"/>

When the arrayCollection data is updated, the List does not update.  In other words, binding is not working.  No errors.

I tested the same approach with the spark DataGrid and the binding works as expected.

The workaround is to explicitly reset the dataProvider back to get it to update the List.

myList.dataProvider = offlineSO.data.myAC;

Why does a bindable dataProvider work fine in DataGrid, but not List in a Flex Mobile Project?

Thanks,

Don