[jayfeather]

I’ve found that if the recipient is wearing headphones/earphones, you can freely interrupt them without getting ducked (and vice-versa). Doesn’t help much when you’re calling multiple people / have to be on speaker, but makes it predictable at least.

[bschwindHN]

Well sure, that's the easy case for echo cancellation (remove the source of echoes entirely).

But we've had solutions to this for decades and it doesn't involve ducking the recipients audio. Apple and their billions of dollars should have had this completely solved by now.