I don't believe it is your fault on that. I pepped 4 of same gauntlet and I have the same problem. It is because the middle pieces are too large and curved. The gauntlet should have been broken into smaller pieces to enable the curvature to show up better. To fix the problem, just apply more bondo to smooth out the surface.
But that shouldn't really happen, since Pepakura, strictly speaking, doesn't know any round surfaces. Maybe it would help to hide fewer fold lines or none at all.
You can also format fold lines differently depending on their angle, that way you have them all and can fold them where needed. To do that, disable the hide almost flat folding lines threshold and format them all with (for example) lighter shades of red and blue. You can just drag a box around all the pages with the pen tool to do this. Then enable the threshold again and repeat the formatting, this time with darker red and blue. The second time you will only catch the folds that are above the threshold, the ones below it will retain their light red and blue formatting.