Mine is doing this same thing.
it will hover at 15-18 feet, and I give (rabbit mode) full down, it will barely go down when I let off it shoots back up.
gear was down, in angle mode
finally turned the GPS off., and it drifted hard to the side but went down relatively OK.
very annoying.
I notice if the H sits in the sun while I calibrate accelerometer, the altitiude will steadily climb.
for instance, it last thought it was at 15 feet while sitting in the grass in my yard.
is there a permanent fix for this?
up and down sticks read fine on the hardware monitor, firmware is upto date.
it needs cooling, or something for whatever tells the beast what its altitude is.