Generally, at all levels of the game (even in the tower) there are events that trigger ambushes, such as bars that emerge at the specified moment to block your way and trigger an ambush, or simply enter a specific area to trigger an ambush.

Steps to perform the bug:

The first thing is to go to a level that has this type of event, the bug is the same in almost the entire game (the only exception is in the "Squid Coast" level).
Now look for a way to activate an ambush following the previous examples and when activating it you will realize that the ambient music of the level is cut off and the music that should be played every time you activate an ambush does not play.
There is a way to fix it in the same game but it stops working when you exit the level and I will also write it here.

Partial bug fix:

There are 2 ways to fix the bug for any level you want but remember that they will stop working when you exit the level.

• The first solution consists of activating an ambush twice in a row without the first ambush you activated having not finished, so the bug would be solved but at the end of the song as a consequence of having defeated all the enemies of the ambush, the final part of the song will not play for some reason.
• The second way to solve the bug is to go through a doorway and activate an ambush and then die 2 times, then activate another ambush without having left through the doorway and thus the bug would be solved and the final part of the song if played.