Hexacopter Hard Landing : PX4 in Altitude,Position and Auto Mode

I am using a Pixhawk-4 flight controller running PX4 FW 1.10.1 on an Hexa-copter drone custom-built. i am facing problem when ever i want to Land my copter in any mode except stabilized , it does not land properly, it detect ground then gain high about 1 to 2 foot then hit ground then gain hight for some time and then get land even keeping the throttle down to zero. It bouncing on ground at the time of landing.

i changed every parameters and setting but with no luck to resolve the issue. below is the check list i have done but the problem is not solve. It is to be noted that i changed the same flight controller pixhawk-4 on other platform which worked completely fine . I used another flight controller on same Hexa-Copter, giving me the same problem.

  1. Tried Different PIDs , Tried P, I and D each at time but no luck.
  2. Tried the Parameter MPC_THR_MIN
  3. Tried the Parameter LNDMC_XY_VEL_MAX
  4. Tried the Parameter LNDMC_Z_VEL_MAX
  5. Tried the Parameter MPC_THR_HOVER
  6. Tried the Parameter MPC_LAND_SPEED
  7. Tried the Parameter MPC_MANTHR_MIN
  8. Tried the Parameter MPC_THR_CURVE
  9. Tried the Parameter MPC_Z_P , MPC_Z_VEL_D, MPC_Z_VEL_I , MPC_Z_VEL_MAX_DN , MPC_Z_VEL_MAX_UP , MPC_Z_VEL_P

i open up the pixhawk-4 hardware and put tissue along with the foam on the pressure sensor but it still does not resolved the issue.

here is the log file review.