Quad-Chute auto trigger due to transition Timeout

Hello everyone,

As the title says I am having an issue regarding the transition phase. The aircraft hovers to the correct altitude and heading no problem, starts the transition and when it reaches the correct airspeed it turns off the main motor and just cruises until the transition timer reaches the end and triggers quad chute. It does not complete the mission but instead just flies perfectly straight-pitched up until it triggers a quad chute and comes to land back down.

This happened in two flights in a row, I tried increasing the timeout timer but that just caused it to go further away in a straight line before triggering quad chute.

It seems the aircraft never leaves the transition phase to full fixed wing flight, what could cause this?

here are the logs:

https://review.px4.io/plot_app?log=e17d4eb6-0256-4d9d-8559-46fd0445351a

Is my understanding incorrect? Is there something else happening in this flight that I am missing, would be very grateful if someone could help out.

Thanks,