Loss of altitude between waypoints

Hello everyone,

I have been flying with APM 2.6 for a couple of months now, and love it. I fly in a bit of a tight space next to a river, and have been trying to design a mission to do auto take off, and then climb to 225 meters above the open field where I fly at.

I noticed last evening that the plane will do the auto take off, and when it hits 65 meters (the altitude set in the take off waypoint), it will turn to face waypoint 2 (the next waypoint), and in that process the throttle goes down to 30 percent in the, the nose drops, and the plane will descend to 55 meters before throttling up and beginning its climb to 225 meters.

This all happened while the plane was flying over the river adjacent to the field :(. I have tried to understand the logic behind his behavior and decided to reach out here to see if there is any insight into why the auto pilot would do this. My thought at this point is that something in the TECS settings needs to be looked at.

I don’t have access to the dataflash logs at this time (will add tonight), but I do have the telemetry logs:

Thank you all so much.