Repro Steps:

1) Create a Page
2) Introduce a Rectangle to the RootGrid of the Page, and from its right-click context menu, navigate to 'Path'-->'Convert to Path'.
3) Select the Path created in Step 2), and navigate to its Transform Properties. Under the Render Transform section, apply any Render Transformation.

Observe how although the shape visually adjusts to reflect the Render Transformation performed, its bounding box remains unchanged (as expected).

4) Right-Click on the Path, and within its context menu, navigate to 'Path', then select 'Flatten transform'.

Observe how the bounding box has 'reset' around the transformation, but the values displayed in its Properties Panel have not changed and still reflect the values input prior to the flattening.

5) Click off/away from the Path (for example, clicking on the Stage).
6) Click back on the Path, and navigate back to its Render Transform properties.

Observe how now, the values displayed, have been correctly 'reset' to reflect the 'reset' in the bounding box that occurred when the Path was flattened.

Expected Results: A Path's Properties immediately update when the Path's Render Transform is flattened.