Currently, when creating a Template, certain Elements within will be pre-bound.
For example, a Button will contain a ContentPresenter that is able to take a Foreground (colour) value.

If the ContentPresenter is removed altogether, and new Elements are introduced to the Template, some Properties of the newly-introduced Elements will find themselves bound, despite having no Bindings active in their Properties.

In this case, replacing a ContentPresenter with a completely fresh TextBlock will result in the TextBlock being coloured by the Button Template's "Foreground" property, despite the TextBlock's 'Foreground' containing no Bindings to the TemplatedParent.

Video attached.

Repro Steps:

1) Create a Project with a MainPage.xaml
2) Introduce a Button to the Stage, and set any Foreground colour to it.
3) Right-Click on the Button, and navigate to 'Templates', 'Button', and then 'Create'.
This will open the Template in the Template Dummy Editor.
4) Select the ContentPresenter, and delete it from within the Template.

5) Introduce a TextBlock into the Template.
Observe how despite being a fresh Element, the TextBlock comes pre-coloured with the colour picked in Step 2).
Observe how the introduced TextBlock has no Bindings on its 'Foreground' Property.

6) From within the Template, MiddleMouseClick over the TextBlock's 'Foreground' Property.
Observe how no changes are observed, and that the colour selected in Step 2) now serves as the Element's 'Default' Value.

7) Right-Click on the Template's default Border element, and from its Context Menu navigate to 'Layout', 'Replace With', then 'Grid'.
8) Add another TextBlock adjacent to the TextBlock introduced in Step 5), side-by-side within the Grid created in Step 7).
Observe how this second TextBlock is also inheriting the Parent Element's 'Foreground' value despite also being fresh/unbound.

Expected Results: Only Elements containing deliberate Bindings reflect the values of another Property.
Expected Results: Introducing a fresh Element into a Template should work exactly as introducing an Element to a Page, in that its visuals reflect the Element's defaults, and is not changed from the Template's values until the Bindings are created.