I can't say anything specific about your problem straight other than Dovo make fine blades & I haven't heard anyone say anything bad about them. I suspect they are the most popular straight razor currently out there. Maybe it's a one off manufacturing fault, maybe not.

I've got one blade - it's the Invisible Edge classic full hollow, & it was definitely shave ready when I got it. It took 2 months for me & my beginner shaving/stropping before it needed honing. I've also heard nothing but good things about T.I.E. I suppose anything is possible & everybody makes mistakes now & then but you should have returned it to T.I.E. before letting your brother loose on it with a hone. You could try emailing Steve at The Invisible Edge for advice but I'm not sure how much joy you'll get now.