Thanks to all the people that tried it, and thanks to all the answers.
The software I used to download the video is IDM.
I myself repeated the process, downloaded the video, WITHOUT CLICKING ON PLAY I choose the times for A and B, I saved the video and got a perfect audio profile.
And I begin to understand what happens. It is related with the space button, it is used to play and stop the video, notice that when you push space to stop the video the video gets frozen, if after that you click on it again, which is play, for a tenth of a second you see the screen in green color and you hear a weird audio sound. My problem is like if I use the space button then when I make the cut that weird audio is recorded.
I use the space button a lot, and it is the only explanation I can think, but I don't have any manner to prove it, I am trying different ways but when I want to get the weird audio I can't

it is so frustrating.
I put all the data you requested, I used MediaINfo to get it:
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : mp4a-40-2
Duration : 1 min 47 s
Bit rate mode : Variable
Bit rate : 126 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 1.60 MiB (9%)
Title : ISO Media file produced by Google Inc.
Encoded date : UTC 2016-08-14 05:00:32
Tagged date : UTC 2016-08-14 05:00:32