I've had it happen more than a few times unfortunately. Never had a loop fail on me yet, but I have had releases malfunction a few times. Or mess around and get the trigger too light.
I have a Rolleraid release that is useless for me. It works ok for my Girfriend because she has a really light draw. However if I use it the string will eventually pinch and slip thru the rollers.
And I have my Jim Dandy fletcher loop release currently being sent back to the factory because it will not stay hooked up. The release doesn't fail, the loop just slips off the hook for some reason when you hit peak weight. It worked really great for a while, now it's not worth a darn. I love the release, but I can't handle wondering if I am going to sock myself in the jaw everytime I draw the bow. I hope they can figure out what is wrong with it.
I have had a bow explode on me at full draw before as well. I either had a cable or a string let loose, I don't remember which. NOT a pleasant thing to have happen. I got smacked in the side of the face with one of the cams and it knocked me down. Didn't really hurt the bow though, the limbs came off is all. I had it all checked out and it was ok. Those dartons can really take a beating!

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Paul