This is more likely NOT a TiVo issue.
The problem is probably with the way Tribune labels the new shows. This issue occurred when Top Chef's new seasons would have the name of the city in the title (Top Chef:Seattle, TC:Chicago, etc.). The new seasons were never picked up by the old SP!
Have you tried canceling the existing SP and recreating it?
"YOU! YES YOU! STAND STILL, LADDIE"
"How can you have any pudding if you don't eat your meat?"