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
9. Save the document
10. Reload the document

After reloading, the shape gets definitely larger (proportionally to the initial
size). Every time the text is edited again (actually, it's enough to
double-click the shape) and the document is saved and reloaded, the box gets
larger too. Several saves/reloads cause the box to exceed page size.

As the reload operation makes the box much larger than the text inside, it's no
longer resized to fit the text.