Rtl type:1 problem

PX4 Autopilot
1

I would like to share my opinion that there seems to be an issue with the RTL logic.

Test conditions are as follows:

  1. RTL TYPE: 1

  2. Firmware versions tested: 1.15.3 & 1.16.0

  3. RTL Altitude: set to 120 m

  4. Frame type: generic VTOL

Observed behavior:

  • Case 1: When operating below the RTL altitude, the vehicle climbs up to 120 m as expected. However, during the return to home, the altitude continuously decreases, and in fixed-wing mode the aircraft eventually collides with the ground.

  • Case 2: When operating above the RTL altitude, the vehicle maintains its current altitude and returns home normally.

I have tested this multiple times in the simulator, but I cannot figure out why it behaves this way.
Is there anyone who can help?