Repro Steps:

1) Create a Project containing a MainPage.xaml
2) Create a Component, and insert a TextBlock within it.
3) Place the Component on the Stage of MainPage.xaml
4) Open the Component, either by double-clicking on it on the Stage, or through the Assets Panel.
5) Create a 'String' DynamicProperty for the Component in its ComponentRoot, and set any word as its Default Value.
6) Select the TextBlock and Bind the 'Text' of the TextBlock to the DynamicProperty. The TextBlock should now display the Default Value.
7) Select the ComponentRoot, expand the DynamicProperty, and change its Default Value to any other word.

Observe how the TextBlock's text does not update to the new default value. Observe how this not only extends to the Stage, but also the Value in the TextBlock's Binding.

6) Close the Component's tab.
Observe how on the Stage of MainPage.xaml, it is displaying the correct Default Value.

7) Re-Open the Component, either by double-clicking on it on the Stage, or through the Assets Panel.
Observe how after a re-open of the Component, it is displaying the correct Default Value.

Expected Results: The Default value of a Component's Default Value is immediately reflected within the Component.