iPhone 16 pro Max speakerphone Volume fluctuating while listening to stereo sound

I noticed a very annoying bug with stereo audio reproduction on the iPhone 16 pro max.

why you listen to ANY audio, in portrait mode and have the volume set higher than 50% (louder is more evident), the center channel seems to continuously bounce between center and bottom speaker, as if the speaker phone volume is pumping and lowering than raising the volume continuously (limiter effect). No setting is enabled in accessibility and you can also notice this by holding the phone in vertical, as you’ll notice that the upper speaker will loose volume and regain it intermittently during playback.

has anyone noticed the same? We should make Apple aware of this as it makes the listening experience unbearable.