FP3/FP3+ mic picking up sounds when not in use and strange high pitch sounds

last night my wife’s FP3 phone was giving out a very high pitched sound intermittently… and it’s done it again today… not sure of the cause, but I’ve noticed that my mic on my FP3 is also picking up sounds on the mic (e.g. if I rub the phone next to the mic) and feeds these back through the speaker at the top of the phone… so I am suspecting some sort of feedback might be happening on my wife’s phone if this is happening there too…

anyone else had similar issues ?

No such issues, but you may have google speech enabled which keeps the mic live at all times, rather than when making calls etc. Add that to the noise cancellation and you can get feedback from ‘rubbing’ the phone and background sounds.