[wkat4242]

This is most likely exactly the problem. It's very unlikely that an ultrasonic cleaner operating at a few kHz will cause interference on Bluetooth.

[somehnguy]

And even if it did - Bluetooth is digital. At worst the music would just stop playing, and at best it would skip - there would be no static.

[stetrain]

Also interference on a digital Bluetooth signal would likely not cause incorrect sound to be played, rather just a pause, stutter, or connection loss.