So I have a cactus sprite like this:
As you can see, it’s nice and round, everything’s fine. When I put it into UE4, though, it suddenly grows a horizontal line on top of it:
What’s the reason behind that and how can I fix it? I can’t simply drag the source region handle lower cause the nearest lower point is low enough to cut a bit of the top of the cactus off so it loses its appearance 
What can I do, then?