I have reported this to Corel through A.R.M., and decided to report it here also so other people could try this and verify it. Steps to reproduce:
1. Make a new document.
2. Make a new master layer.
3. Make a paragraph text object on the just created master layer.
4. Make a new page.
5. Save as old version.
Applies to SP1 at least, I haven't tried it in pre-SP1 installation. There are other problems with the layers as well (the layer managing is a mess, especially if you need to save old version files), but that's an issue for another post.