Prop plane thrust going crazy after completely dethrottling (Tutorial design)

so while dying the first plane contract, the prop enginese on the plane go completely Haywire and proceed to slam the plane into the ground after dethrottling, it doesnt happen immediently but happened after the props slowed down for 2-3 seconds like on this recording here: https://cdn.discordapp.com/attachments/570416065964933141/1126531600369332234/2023-07-06_17-12-38.mp4