Tilemap lighting issue

[Kallenm]

Hey Thanks for providing this asset. I'm getting a visual artifact and just wondering if you have any ideas. I use a tilemap to draw my isometric terrain and it seems when there is a little overlap between the tiles the lighting is brighter. You can see the difference between having the clouds on and off in my screenshots below. Notice the edges of the tiles really stand out. I assume this is from overdraw but I can't seem to get the tile sizes just right so its no longer a problem. I am using the Sprites/Diffuse shader as you request for 2D scenes.