Those square tubes never passed my "eyeball engineering" test. Always looked to me like a problem waiting to happen. That bottom corner is one of the most stressed area in the diamond when you come down hard from a jump (tension) or either hit a pothole or the brake hard (compression). On top of that, the best shape for torsional stiffness and strength is a tube.

Really, a finite elements analysis (FEM) needs to be done with a really good simulated loads that reflect reality. Maybe they ran a lesser FEM and this looked good, but an engineer should also be able to step back and ask "does this make sense?"

I wouldn't trust a weld there for a second. (Well, maybe the first hundred miles.) But I;d be thinking "this weld has added additional stresses to this area. Given that tube shape , am I OK with that?"

To add to that is my concern about the location. If it were to fail, the front wheel will no longer be rigidly attached to the frame and the job of supporting the front end gets passed to the top tube; a job no one ever dreamed it would see. THis wold be ging through my mind eeery time I went downhill.

Ben