LIDAR RF MINI problem on Copter 3.6.4 Hexa (pichawk)

Hi guys!

Could you help me with LIDAR TF MINI on my hexa drone? I got weard crash list time when i was flying. Everything was fine, first flight went 100% correct. Battery Change and secound fly, auto mission went 100% fine until landing. Drone starter AutoLanding procedure, touched the ground and after few secound make a prontflip crash (looks like add pitch forword, drone just lean forward and crashed).
Logs looks normally except Lidar logs. When i looked at RFND lod it looks like in mid flight (after abou 15 minutes of flying)Lidar get info that he is on 4 meters (even thou the drone was at 30meters) and he keeps this 4 meters. Drone started autoland, touched the gound and lindar was still saying that it is on 4 meters altitude. After about 8 secound of beeing on the ground, drone just pitched forward… The End…

What couse this? Any Ideas? No EKF ERROR warning what so ever

pls help