Parachute not opening in mission

I added a DO_PARACHUTE (with parameter 2 for releasing) command after the last WP in my auto mission, as described in the arduplane documentation. However, the parachute is not opening and the plane continues to RTL mode. When I upload the command in an auto mission without WPs and without running the motor on the ground, everything is working as expected.

Do you have any suggestions what could be the issue?