exporting fbx for ue4 with merge uvs by type creates maps that all match except for the orm map. the diffuse and normal maps generated line up perfectly but the orm map is completely different on where the mesh islands are located. this creates terrible lighting/roughness/specular/metallic/reflections and overall cannot be used. regardless of whether in ue4 or not these exported maps do not match and cannot be used together
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Thanks for your help!
The attached images was the result in my end.
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