Quad always starts in guided mode

Hi all,

We took our recently built quadcopter for its first flights yesterday. For some reason, upon arming, the copter always starts in guided flight mode, and attempts to go straight up, with no pilot control possible (the copter was tethered so we don’t know how high it would have tried to go).

We don’t have an RC connected, and are controlling via a PS4 controller input over mavlink. As such, the RC preflight checks are disabled, and I wondered if it might have something to do with this? We are using QGroundControl, and even when I explicitly set the flight mode on the startup screen to “stabilize”, it still started up in guided mode.

We are running a Pixhawk 4 flashed with the latest stable firmware.

Any help or ideas would be much appreciated.