I was looking at your sweeps in REW, and noticed they were over 95dB. That may not be an issue, but you can sweep at a much lower SPL, if in a quiet environment.
I did notice a peak in 2nd order distortion on the mid around 1.5k. It shows both on and off axis. The tweeter measured considerably better at 1.5k. Sometimes a loose mounting screw can cause such a thing. I think an overly tight screw can as well. My driver baskets are thick aluminum. I usually tighten the screws with a minimal amount of torque. The ideal tightness may vary with several factors.
I did notice a peak in 2nd order distortion on the mid around 1.5k. It shows both on and off axis. The tweeter measured considerably better at 1.5k. Sometimes a loose mounting screw can cause such a thing. I think an overly tight screw can as well. My driver baskets are thick aluminum. I usually tighten the screws with a minimal amount of torque. The ideal tightness may vary with several factors.