Are two or more circuit courts in conflict? If no, then I'm not surprised.
I don't know. I don't follow the gun cases closely, just learned about the outcome of Heller II a few days ago.
Scalia left openings big enough for a truck to drive through, when he composed the Heller decision. I didn't and don't see that case as a RKBA success. It is more of a "pivot point," and now the district and circuit courts are using it to uphold most any restriction short of outright ban on 100% of firearms.
Anyway, thinking that the courts are pro-RKBA is a grave error. The courts are hostile to the RKBA. Like you, I'd be most surprised if the circuits allowed a split on the constitutionality of banning magazines above XYZ capacity.