Thanks for the response. I verified the triangles were symmetrical from conversion, and there is only one vertex on the top middle and bottom.
After more research I found this issue on Github where someone reported similar seams on a flat plane in 3.js. It turned out to be due to bent normals at the seam due to numerical precision issues at 0: Seams with normal map and mirrored uvs · Issue #18565 · mrdoob/three.js · GitHub
I subtracted .003921 from the x channel in the normal map in my material and the seam was gone! I guess Unreal doesn’t natively do this. If anyone has any other ideas or workarounds please let me know. Here is the fixed image with a round bevel in the normal map plane and the seam is completely gone:
