I have this happen to me often enough to be quite infuriating. I now have Word running in the background just so I can cut and paste my descriptions from AW2000 as a back up for when AW corrupts everything I wrote. It happens when I leave the description field for most any reason. Not every time mind you. I'd say about 10 or 15% of the time. And it always seems to do it on the new item that I forgot to make a copy of.
Or a similar thing is it will revert back to the inventory item that I copied it from. I copy an inventory item. Make my changes in the description, switch to a different view and loss all my modifications.