so i am tryng to import tiled landscape from world machine and this is what i get
https://gyazo.com/5557acd87f6ee1ed4d1c14fcaf05f8a3
You need to change tiling settings for world machine, they have a separate option to flip Y coordinate. Try that, otherwise I can check how I’ve exported it last time.
It looks like i had option flip Y turned on in world machine and in ue4 when importing. i turned off in ue4 and it worked fine.