I am having the same issue.... I upgraded my Phantom 2+ to the latest S/W firmware (3.06) Phantom Vision Assistant. Did full IMU calibration, calibrated RC controller, calibrated Phantom, every thing went well. Took it out to the field to fly. Did the compass dance, got course lock and home lock (11 Satellites). Flew arounnd for a while in GPS mode. Brought it back to practice landing. As I descended from 30 feet (straight down on the stick) the Phantom yawed 5 to 10 degrees, I corrected it back and tried to descend and it did it again. Tried 3 or 4 more times, same results. Got out the laptop re-calibrated the RC controller sticks, and the phantom sticks. Tried again, Same results........ It makes it difficult to land on a specific spot.
I was not having this issue before the upgrade.
Anyone know how to fix it, other things to check????
I will try the tests suggested above.
I also noticed the default gains have changed from 3.0, could that be it?