Strange noise on recorded videos

[gabvigno]

Good morning, in every video shot with Zenfone 6 (latest update WW-17.1810.1911.110) , it is present a strange noise (like tapping on the microphone). I'm attaching a small video which shows the problem (Zenfone was steady during this recording).
Since this is not the first problem (see the other discussion "Headphone Audio Static?") i'm starting to think that my unit is defective.

[gabvigno]

Any feedback from moderators?

[gabvigno]

May we know if it is software or hardware related issue?

[LP_ASUS]

I can see what the software team thinks about that video.

[LP_ASUS]

Can you test your microphone for me?
1) Go to the calculator app.
2) Type .12345+=
3) In the test menu, select "Single Test"
4) Scroll down the test list to "BoardMic" and "BoardMic2 Test". Please run both of those to make sure your mic is working properly.

[gabvigno]

Boardmic is OK but in the Boardmic2 test my voice is cut after 1 second.