iPhone 6s Plus, static through earphones when locked

Hi,

Just wondering if anyone else has noticed this or can replicate it on their 6s Plus.

You have to be in a quiet environment to hear it though (and it doesn't matter if the headphone volume is set low or high).

So, if my phone is locked, and the screen is off (i.e. black), and I have NO music playing, and then I 'wake' my phone up, either by raising the phone or pressing the side button, I can hear a very subtle and brief static or crackling noise through the headphones. Sometimes it's more noticeable than others, and on the odd occasion I can't hear any static.

Also, it's sometimes audible when the phone goes back to 'sleep' (i.e. which is once the phone has been locked again, and a couple of seconds after the screen goes off/black).

I'm presuming this is a bug in iOS10, rather than a hardware fault as I've noticed it on two different brand new 6s Pluses. (but strangely not on my old 6s)

Thanks