Hmm, the game has action music system, which means that many actions, for example holding someone up or punching (even a crate or a window), will trigger the music to change. After a while, if no other actions occur, the music returns to the normal, 'stalking' type again.

This can sometimes be annoying in the tutorial especially, when the music changes back and forth when e.g. breaking the crates or windows.

If this doesn't explain the problem, see if you can figure out how to recreate the issue and let us know. Thank you! :)