I think there is something wrong with the Bell sound sample or something. Maybe it isn't the right length of sample?

Reproduction:
Place 5 audio parts. Adjust the pitches to something different for each and assign keys 1-5 to play them. If you change to using the Bell sound in particular (maybe others, Flute seems to work)... Bell will cause it to glitch and different audio devices to all play the same/different frequencies.

If you spam the keys you can kinda 'fix' it and get back to having different tones but it will never 'work right'.