Mazda 3 1.5 AT 2018 Short whistle sound during transmission switch from 2nd to 3d

Hello all.
I have a problem with my new Mazda 3 1.5 AT 2018, I hear whistle (sounds like a turbo blow-off valve) during transmission switch from 2nd to 3d, every day and after every traffic light.
But when I just bought it (about 1 year ago) all was fine (no any strange sounds) and it appeared after 1-2 months.
My dealer is not located in my town, so I can't be very often there.
Previously I was there half year ago (on service maintenance #0), I told to master abut the appeared problem, he confirmed that strange sound appears.
Then after a few weeks, he told me that they are can't find any TSBs about this problem, and maybe it is normal.
Then I've talked with dealer warranty specialist, and we have agreed that next time(at the end of September) they will take some data from the car and send it to the Mazda Corp if needed( I was angry by the fact that the master did not do this during previous service maintenance #0).
So now I'm waiting, and trying to collect available information about this issue.
Also I know one guy with the same mazda and same problem) and I as understand this is very common issue for 1.5 + AT, many people just close their eyes on this problem.
But for me this is very disappointing issue, because I bought new car , and I don't think this is normal.
sound it's very audible(me and my wife hear it), so I don't think it is normal.
I think that Mazda engineers should investigate issue and create corresponding TSBs to solve it, or replace defected detail/car.

Also I tried to create a video with this sound.
Here is a lot of videos (6)
http://bit.ly/2ku1ruL

Maybe someone has same problem or know anything about it (maybe links to Tsbs) ?
Thanks (And sorry for my English)

After last visit to the dealer, they told me that Mazda says that this kind of sound is Normal AT behavior!
So, actually I don't now what I can do (((((
This sound is really a problem for me and my family (