Yes, these transmission computers have been replaced under warranty. My mom's car had it replaced under warranty for a different problem.
My 97 C280 does the same exact thing on the 4-3 downshift, but I am willing to live with it as everything else works fine and I don't mind a harsh downshift. I would follow John's advice and get on them, how did they suddenly know about the problem when the updated computer has been around for a few years?
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record