Android : android.provider.MediaStore.Images.ImageColumns.DATE_TAKEN return wrong data

I have an image taken with an iPhone that already have GPS data on it. When I put it in my Android phone and take the taken date of it by using android.provider.MediaStore.Images.ImageColumns.DATE_TAKEN, the time return is always the original date in EXIF + the timezone of my phone (original is 13:23, time returned is 20:23). I look around in Android Source Code and found that when image has GPSTimeStamp attribute in EXIF, that timestamp will be saved as DATE_TAKEN (Android said it UTC time). However, when I look into the "real" EXIF, the GPSTimeStamp is 04:23 (-9 hours instead of +9 hours). I really don't understand why DATE_TAKEN is returned as 20:23 and not 04:23. A link with official explanation is really appreciated