Pitch Fluctuation In Music During Movie

I just started to watch movies on Kodi (on Raspberry Pi 3), and noticed that in some movies the pitch of the music is bent from time to time (slows down for a second and comes back to its normal pitch). It never happens during speech, just during music. I’m sure it has to do something with the settings because I don’t have problems like this with these movies while watching them on my streamer.. My sound output is the TV speakers, I do not have an external receiver. Solution anyone ??