@pascal I think I understand your post now. If the blend edge of the pipe was straight, or perpendicular (normal) to the curvature of the pipe, then it would and it does create a G2 edge curve. Like this
But since the edge of the pipe surface has been trim across the surface (slightly) then the blend curve curvature isn't normal to edge curve. If that makes any sense.
So when you run the blendSrf command, like you said, it doesn't pay attention to adjacent curves, but if you put a G2 blend edge curve there and run the sweep2 command then you can achieve it.