It's difficult to notice any problems with your curvature map. Try pressing the B key (keep pressing until curvature shows up in the top right corner), and check out the baked results that way (press M to return to full material). If you see a seam here, try lowering the "details" slider of your curvature baker. Keep lowering it until the seam goes away. I've noticed that if the details slider is too high, it detects UV seams as well as small variations in your low poly vs high poly.
If that doesn't work, you may try adjusting your high poly vs low poly in that specific area.