GPS_Atti was a change made by DJI when the GO app was released. Several other names were changed with in the flight data descriptions at that time as well. Developers of flight loggers and convertors simply grand-fathered those same names into their work as to not cause any confusion. Prior to posting I checked the logs from 3 different developers and each of them use the now common GPS_Atti in their work.
Healthydrones only shows a basic summary and very little information for a proper understanding of what actually happened.
You'll do a lot better by going to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link and you can get plenty of help too.