Those UVs look drastically different and it’s likely that the second is set to be the Lightmap, but can you check in the Static Mesh Editor under the Static Mesh Settings > Lightmap Coordinate Index (under the rollout arrow) and make sure that that is set to 1.
If that doesn’t work, would you be able to share the asset and I can have a look in a scene and see what’s going on or if you have a sample project with just this asset and the lighting setup I could go straight from there.
You can share this on the forums privately if you’d like: https://forums.unrealengine.com/private.php?do=newpm&u=4894