Strange RTL behavior?

Maidened my AR wing pro, with a mission in 2 stages, takeoff and RTL. Takeoff set to 50m, RTL altitude was default, 100m.
After takeoff, the wing started to descend rapidly but barely saved it from crashing into the ground.
Is the baro faulty ? FC is an omnibus f4proV3.
I don’t know how to interpret the log file, help needed.

My log file: Download link for 2023-05-18 16-49-47.bin

https://youtube.com/shorts/ebsrH9WM9lQ?feature=share

According to your log, the aircraft entered RTL mode immediately after takeoff completion and attempted to enter a 75m radius orbit around the home position. Even though the aircraft did not gained enough speed (ground speed=10m/s, no airspeed data available), the aircraft rolled significantly, reached a bank angle of 75 degrees. As a result, there was not enough lift and altitude was lost. During descent, the aircraft switched to CRUSE mode, the roll angle leveled off, lift was recovered, and the aircraft climbed.

If an airspeed sensor had been configured, stall prevention would have worked to reduce the roll angle.

Agree with that. I suggest limiting bank angle to within airframe’s envelope.

Also suggest getting an airspeed sensor since the frame hit 42 m/s according to the GPS – that’s 150 kph!