Pixhawk burn the digital servo when I added the parachute function

Hello everyone. I am using the pixhawk with a flywing for mapping. I used to use a switch to release a parachute and it worked well. Today, I am using the parachute function to release the parachute, sometimes it worked well, but sometimes it burned servos. I used a relay for trigging the camera. Have anyone met this problem? Please give me some advice. Thank you.