Yeah, it just looks like you need to use a stronger glue, let it sit for a long while to make sure it is fully dried and cured before you move onto the back.
By the way, I put industrial strength velcro on the backs of mine to be able to adjust for leg thickness, either if I lose or gain weight, or if I let someone borrow my armor, they can adjust it for their legs, so only the fronts are glued on mine.