Hi All,
My previous issue has been solved here, so, I post a new one. 
So, my setup is Pixhawk Mini with Copter 3.6.7 v2 on it. Previously I completed the Autotune and the AutoTrim, and it has flown as expected.
Recently I bought a LidarLite V3 which I wanted to use as altimeter to replace the Maxbotix clone sonar. I installed the lidar as mentioned (except the rangefinder type, I set it to 21 instead of 15 because, like others, I also experienced 9.some offset but on 21 setting the lidar is giving nearly cm accurate readings), and it is working as expected. I left the sonar in the craft, turned to 180 deg, for act as backward proximity sensor, with the needed parameter setup. For test purposes I also activated the EK3…
At the test flight I experienced strange behavior… In Stabilized mode everything was fine. In any assisted flight mode the craft leaned forward to ~5-10 degrees and started to move away. I needed to react with pulling the pitch slightly back. Switching back to Stabilized made the craft be leveled.
After this I inactivated the EK3, and today I also made a test flight. Stab is OK, PosHold and Loiter is also OK but in AltHold the forward leaning is still present… I provoked the object avoidance routine, and the craft is stopping when I directed it’s back toward a wall in Loiter and in AltHold as well. But I can not deal with the leaning forward in AltHold… I tried to find the cause in the log, but I was not succesful…
Any help is highly appreciated!