Dani is correct that we update the demo sites when a new version of the product is released. This way, the demo is giving you an accurate representation of what you can/cannot do with the product.
There is currently not a fix for this table issue. So far, we have not been able to reproduce it consistently to come up with a fix. If a fix is added and included in the product - rest assured that it will also be included in the demo.
One thing to keep in mind is that PowerCMS currently uses our older iRite instead of the HTML Editor Dreamweaver extension that may not have this table issue. The next version of PowerCMS will be using HTML Editor and will probably not have this issue. It takes time to update products and create new releases - laziness is not the issue.