Did you merge them in your modeling software or with unreal? If you used ue, what merging method did you use? It could be a normals issue.
And most importantly, are you shaping each individual triangle specifically in this way, to give the feeling of a pattern? Because in that case you can easily get a texture with that pattern to avoid unnecessary geometry.
If they are all distinct geometries, I misunderstood the problem, however if you made them in array, check that you have set the array correctly. It seems to be a constant offset problem on the z-axis.
@2DNED