Audio in NDLA virtual tour does not stop on scene change using ipads

On various versions and sizes of ipads, using chrome and safari, it seems that the audio (background sound) does not stop when one exits a scene and enters another. This is how it plays out for me: I turn on audio in opening scene 1 and it starts to play --> move on to scene 2, but the audio from scene 1 still plays. The audio in scene 2 seems to be turned off as default. When I click on the audio in scene 2 it starts to play on top of the audio from scene 1. When I try to turn the audio off in scene 2 the audio button is unresponsive. --> Moving on to the next scene 3, the audio there piles up on top of the audio from scene 1 and 2. Quite the symphony, actually. The tour is built in lumi.education.