I have the same issue and the same warning in the app. I played around with it a few times and by luck, I was able to change the tone. Need to pay attention to the blue ‘Ring’ light in front the chime. When it stops blinking, it’s done updating. I flipped back to the previous page immediately by hitting the back arrow before the warning popped up, and then open Audio Settings again. I got it to work ~50% of the times. Still, it is annoying and does not make sense to take minutes to choose a tone. It will take half a day to test out all the ring tones. Now I am on westminster and I am afraid to make a change.