[arrowhead]

A small tree branch in the way, maybe? Your limb hit something as they moved forward. I've seen mechanicals deploy and cause this also.(so many times that I refuse to use them)

 

[arrowhead]

I've had several customers in the store with the same problem. It's almost always the mechanicals. When we troubleshoot them....I stand downrange behind a concrete wall and let them shoot past me to the target. Many times I've heard the blades deploy the instant the trigger broke. Sounds ike a bottle rocket coming at you...going past you.