One hour after my first 20-minute ride with new inner tube it exploded with "ps-BAH!" sound. Also, as you can see on the photo, two bulges appeared near the hole. The tire (25mm) allows up to 8 bar (116 psi) , I inflated it to around 7.5 (108 psi). Do you think it's simply a production defect of the tube?
EDIT: it's not a long cut on the photo, it's a seam. See full res image