I wonder if "certain MP3-related patents" is an attempt by Fraunhofer to narrow or clarify their claim. I have a couple guesses.

1. Perhaps Fraunhofer doesn't own all the patents associated with MP3 and they only want to claim terminating the licensing for their own IP.

2. Perhaps they meant "certain patents related to MP3". In other words, Fraunhofer licensing for other IP not related to MP3 could still be in effect.