Yes, same thing with mine, and I live start it. I park mine in my garage and am hearing it at 20F and lower. About 3 - 5 seconds of whistling. Probably an accessory waking up, alternator, AC compressor...

 

I get the same whistling sound too when I start my sorento. Weird thing is that it’s not consistent. So far I only heard it twice in the past couple of weeks. Just went to Kia dealership for my 1st oil change today and mentioned it to them. But they said they can’t say what it is until they hear it themselves. I asked them if there’s anyone complained like me and they said no. They also said there’s no pending issue sent to them from Kia. I told them I’ll record it and will send them the next time I hear it.

I hope it’s nothing serious though considering I got my car last July and it’s barely 5000km.

 

I have noticed this too, only recently in the bitter cold. I live start it as well, and it only lasts a matter of seconds - I haven't timed it, but it can't be more than 20 seconds before the whistle-like sound goes away.
My Sorento is pretty new, I just got it in September, and it has just over 3000 miles - in fact it just got its first oil change 2.5 weeks ago.

 

The link is in my original post.