Imagine there's a signal line that's pegged at 0v and when the volume circuit bridge connects it takes it to 5v to indicate user input. The other end may have been programmed so as soon as it sees >0.2v then it needs to change the volume but this amount is so low and thus so sensitive it responds to interference often. All that needs to happen is the OS needs to configure the minimum voltage indicator to be raised by X, job done.
Honestly, I've seen tons of worse issues on handsets in the last few years, even the big boys arn't against trying to make howlers like their entire radio shutting down after a 60 minute call etc... It's pretty amusing this has happened don't get me wrong but my advise to everyone is to keep calm and carry on - even if this doesn't fix the issue (but I highly expect it to) then there will be a final fix delivered for this as it's reference.