It's hard to tell from the photo, but it looks like a bit of a deformity that may have environmental causes such as imperfect pollination due to all the rain we've been having. The pods should be okay to eat, but if you want to be sure you can send a sample to the Penn State plant clinic for analysis. You can do it yourself by following the directions at their website, or you can take it to your local Penn State Extension and have a Master Gardener help you.