If it is like that on your present unit it will more then like be like that on any other unit. Simply don't leave something displayed on screen for long periods of time. There are/is fetrures built into the OS to stop this from happening. Screen saver is one, the other is to set the system to turn off the screen after a shorter period of time.
IMHO there is not reason in the world to not use one of those features and no reason to leave the same thing displayed on the screen. Not to do so will cause your Mac to ware out faster then normal, especially the screen.
If you aren't going to use the computer for an extended period of time, which I consider 20 minutes an extended period, set it into sleep mode.
20 minutes is the time it takes to go to the kitchen and get a cup of coffee...a $2000 laptop whose only selling feature is the **** SCREEN shouldn't have issues sitting on the same image for 3 hours let alone 20 minutes.
My entry-level 13 inch Macbook Pro at half the price doesn't have that issue and I leave it sitting with webpages open all the time.