Steps to reproduce:

1. Create a new document
2. Show the Drawing toolbar (View/Toolbar/Drawing)
3. Create a Rectangle, Rounded basic shape of any size
4. Double click a shape
5. Enter any text
6. Click outside the shape, then right-click on the shape and select Text
7. Check the "Resize shape to fit text" checkbox
8. Click OK (the shape should get resized)
9. Resize the shape by dragging the bottom-right corner.
10. Press Ctrl+Z to undo resizing

The Undo operation doesn't restore the previous size of the box (the one before
step 9), however, it changes the box position (and it isn't supposed to do that).