Air 3 (sometimes) suddenly gives ATTI warning, but GPS signal is white.

[Meta4]

I found many with weak GPS signal warning, but with 11-13 satellites connected.

That's because you need enough sats AND the sats have to be spread across a wide enough part of the sky.
11-13 sats will usually not be enough to have good GPS data.

I never fly without checking for white satellite icon, why would I get a warning?

I would have to see data from one such flight to tell.
None of the flights you provided data for show you getting a warning of Atti Mode after acquiring GPS.

Please let me know if something is strange in these logs. Or if I just don`t understand the drone enough.

Your flight data is good.
What the flight records show for those four flights is:
26 Nov: Flight lasted 2 mins, up to 13-14 sats, but GPS level was stayed at 0/5
29 Dec: Flight was normal with full GPS after 8 seconds
1 Jan: Flight was normal with full GPS after 23 seconds
9 Jan No sats - no GPS flight for 1:19, but height was always less than one metre.

I can't see where you were for the first and last flights.
Were they out in the open or could buildings, tree cover or other obstacles be blocking GPS reception?

 

[msinger]

I put them in my Google drive

This is the only flight that shows ATTI mode:

DJI Flight Log Viewer - PhantomHelp.com

That occurred right at the start of the flight log where you took off before GPS was available

 

[monchan]

I`ll keep look through the logs, got my pc opening those csv files now.
They must be something.
Thanks again.