I've had a couple with zebra lams that did it. The grain ran across lam at about a 45* and I had back and belly lams with grain running same way .
Take a zebra lam with angled grain with a couple fingers on each end and flex it in a half circle and watch it. That is .060 of total stack on my bows so it can matter...
If you could look thru limb and cores, the grain should be opposite back and belly making sort of an x , or better yet, use straight grain...