as already mentioned by handirifle, looking down the string will usually show up any twist in the tips–
When I string my bow I always Double check – to be sure the string is actually in the groove of the string nock.
—-Once I strung up and visually checked [ which I do everytime] and noticed one side was off — maybe this happened to you?
always good to check the nocks on each limb before shooting IMHO
Scout