Terrain Radar -Sudden Altitude drop

ArduCopter Copter 4.4
1

Hello all

I am having hexacopter for an agriculture spraying purposes.I am facing some issues please find below.

Issues:
1.At low altitude flying (less than 2 m) sudden drop without RCIN control.
2.While take off also there will be altitude drop.
3.We are using terrain follow radar JIYI .
4.If we fly above 3 m the drone altitude will not drop.

Please find the log-Logs

Thanks for the advance

2

Has this been tuned using known best practices ?