If there is wind it is normal. If there is no wind, it should be almost flat. Try to recalibrate the IMU, at least check the value of the sensors when the P3 is on a flat leveled surface.
View attachment 60874
The value for the Gyroscope should be all 0.00 (no rotation)
The values for Acceleration should be 0.00, 0.00, -1.00 and 1.00 (here in my screenshoot it is not as the P3 was not on a flat leveled surface).
For the compass values, it can vary a lot. At least the "Mod" value should be in the range of 1300 - 1450 depending where you are located in the world.
These values are live so you can move you P3 and see the effect on the screen. For the compas, if you rotate the P3 by 90°, the value between X and Y should almost swap (if you have X:70, Y:800, then you can get after rotation by example X:700,Y:120) showing that the compas operate correctly.