Oh man
I feel your pain.
That looked sooo sweet too.
Forgive me if I'm stating the bleedin' obvious here
I'm sure you can see for yourself you'd left virtually no horn at the nock.
I generally have very little groove a the side of the tip, especially if you are making 'em reall skinny, After all the string moves up and down along the side as the string angle changes so it doesn't want to sit in a groove.
Dunno if I'm getting fanciful now, but if the string is tight in a groove up the side of the nock, then as the string angle changes it will be sort of trying to lever the tip over towards the back of the bow.
See attached pic... ok it's only from a weedy 50# bow but it shows what I mean (btw it's 1/2" wide at it's widest point)
Maybe that's why full ELB horn nocks are a good idea? you retain a full circle of horn where the string sits* and thay can still be pretty skinny.
Oh dude, that must've felt like a kick in the guts.
Again oppologies... I don't mean to treat you like some newbie..... (tugs forelock and backs carefully away from the keyboard)
Del
* I have on occasion had 'em where the wood peeked through a tiny bit at the side.