This is one of those things where I’d just need more information. My first thought is that it’s a problem in UE4, and though tracking down problems is best done linearly, follow the steps from begin to end, I just can’t think of any exporting issue that would cause this, and if it did, it would certainly be new to me. With that said, the only thing I can even think that it possibly could be is the blend type. But yeah, otherwise I really don’t know.
So the best I can do is to either ask you to post more info about your UE4 setup, as much as you can or willing to share, AnimBP… etc. or send me a PM and then we can deal with it more privately so I’d ask if you can send me your actual files, anything included for the UE4 stuff to work. You can Migrate just that stuff, the bare minimum to a clean project and send me that.
If it’s something simple, then some screen shots of your setup can usually reveal the problem but otherwise it’s very time consuming to go back and forth on what it COULD be. I’ve never had this problem myself, so I can’t say where to look or what not to do… you know.
Sorry I can’t provide a more useful answer, but I’m willing to try work it out with you if you want to, but I probably would need to get my hands on your UE4 project, even just in a bare form just to see what’s going on. Unless you’d rather go through Answerhub and see if people have had similar problems. I’ll leave you the choice… 