Weird line showing up on object? Could be a shadow issue?

Hello,

So I'm making a bed, and I made my frame separate from my mattress. 

I cloned a floor statue for this.

I'm having an issue where this small maybe 1x1 pixel line is showing up? I think its a shadow issue?

So I tried a few things..... 

I took a look at my texture to make sure I hadn't missed something, and my texture was fine, it also doesn't have this issue in TS4 studios only in game.

I thought, maybe its a mesh issue? But I couldn't really see anything on my 3D modeling software that would be an issue. 

I followed this tutorial - but it didn't work, I also deleted the occluder's shadows in Light in the ware house tab - didn't work

I tried going with out a Shadow LOD and that didn't make it go away either....

I really am not sure what to do :(

Here's a picture of what it looks like

example 1

example 2

Please help