@Learner: It seems the "add_date" field in [xcart_products] table is changing too. This needs an investigation. Normally if a product has a field "add_date" set up already, it should not be changed. If it is changing by default after a modification in product information, you should report this to QT, it is a program logic issue there. Field "add_date" means date of creation, changing text in descriptions, price, ..., should not update this field to current date.
Use this thread to see and modify your "add_date" field in Admin -> Product page:
http://forum.x-cart.com/showthread.php?t=63608&highlight=add_date
After you customized your code you can check what time is it after you modify description. If I am right, we should report this program logic issue.