These are things I would check first:
Nock groves and Alignment.....they have to be right on money or string loop will pull tip to one side or another.
Lower one nock side (looking from the belly) to pull tip that way.
And/Or...file the side of the nock deeper that the lean is on (looking from the belly) about 1/16" increments. careful here not to lower the nock but cut deeper horizontal into tip.
String loop......a string wound up to tight will roll at the loop joint and could cause a flimsy tip to fade over.
Also if your making a 2" bow use a 2" form and so on. This helps makes sure everything is square in layup. I masking tape my limbs down to form before i add air...It's square everytime.
hope this helps