Why is music in the videos gone ?

I was watching some DBZA and the intro music (Cha La Head Cha La) was muted. I thought it was a video glitch, but the rest of the audio in the video is fine, it's just the music and the disclaimer intro.
https://www.youtube.com/watch?v=dcHIikdrhjQ&list=PL6EC7B047181AD013&index=43

I don't know if it's some automatic copyright bot or what, but in other DBZA episodes, the music for the intro, and sometimes it isn't. I might be imagining things.