Weird lines on uv map


As you can see on the top right theres a weird line on the Uv and why is this happening and also when i import it to ue4 its fine but when i build the lightning in ue4 it says uv overlaps by 41 percent is this because of the uv? and if it is then how to solve it?

but when i build the lightning in ue4 it says uv overlaps by 41 percent is this because of the uv?
Overlapping faces in the UVs so you are trying to bake different things to the same part of the texture which obviously you cannot do.

Actually look at the UVs to see where these lines appear from on your model.
It’s most likely down to poor unwrapping.
Check for duplicate and overlapping geometry in your model.
If you have faces > 4 sides then convert to quads

poor unwrapping? but i use smart uv project