Different constraint behavior?

I just wanted to ask about some behavior toward the end of this tutorial; I'm pretty sure I followed what was going on closely, but when I used the Fixed constraint on the A-pillar bar, it only fixed that and made the lower fillet black, leaving the upper fillet and top bar unconstrained/blue... The top bar is dimensioned to the same 900mm, and meets the original hoop's fillet at the midpoint just like the example, and the upper fillet's radius is the same 150mm with the lower fillet also just inheriting this via an Equal constraint. Did Fusion change behavior? If so, any thoughts on the best way to resolve this without over-relying on Fixed or anything? My first thought is to just Fix the top bar or the upper fillet and see if that blacks out the rest of the sketch, but I don't want to use Fixed more than necessary, and I don't want to gloss over a mistake that made my model behave differently. (For completeness, Fixing either the upper fillet OR the top bar seems to complete the constraint; I'm not sure why the combination of a fillet with a dimensioned radius, a dimensioned top bar, and defined end points isn't sufficient to define everything.)

For anyone else who has the same issue, I found where I got it wrong. At the point where you're sketching the A-pillar in the front view, Connor places the top of that line off the end of the straight section of the rear hoop; I'd placed it right on the end of the straight at the joint with the fillet.

I'm still not 100% sure I've got the mechanism right, but although I had Snap off, it kinda seems like ending that A-pillar bar at the height of the junction between the rear hoop's straight run and fillet somehow got in the way of letting the constraints coalesce...

Or maybe the more applicable answer is that if you're having a similar issue, go back over the individual points in the video watching closely 'til you see a discrepancy! Perhaps my attempt to take notes, work Fusion, and watch all at the same time was a bit of a miss...