It looks like it was just an issue that it was using the generated lightmap UV’s when you imported to UE4, if you have your own already setup, then make sure to uncheck that option when you import.
As for the UV’s, make sure you have enough space between the UV islands and that your lightmap resolution is high enough. Also make sure your lightmap coordinate index setting is set to the correct UV channel, if you have 2 channels it will by default set the second channel as the lightmap UV channel.