For users with long Phantom 2 flight experiences, have you ever encountered a situation where you let the quad go off and then leave it in a steady hover only to find out a few seconds later that it is slowly descending? It almost looks like it can't carry itself. When hovering, i had to apply a bit of throttle to keep it from landing or crashing on the ground. When moving forward or back, I had to apply a compensating amount of throttle to keep it from landing like a plane on the runway. This was after I did another Adv IMU calib, though I don't think it had anything to do with it. Before fligt: P2, P.Assistant 3.6, all latest FW,Home Loc locked, Compass Dance done, Batt at 80%, Tx at 100%, Phantom Mode Tx. Any tips to get rid of this auto slow descent?