The problem should be resolved with lib version 2016.1.125.
The issue actually presented itself when using a CellEditTemplateSelector. It seemed to work fine when using the celltemplateselector. The issue with using the celltemplateselector for us is we cannot have the grid in a constantly editable state. Also, doing it this way does not go through the dynamic object TrySetMember when changing the values for the cell. When setting the CellEditTemplateSelector the CommitEdit action for the cell would call the TrySetMember on the Dynamic object but would pass in null for the value. The SetMemberBinder would be correct, so it would set the property to null.