Random Line Appearing on Moving Texture Node

Question

I have several texture nodes which move to right constantly. For some reason, one of the types of texture nodes generates a white line in-between itself and the next node when moving, only when moving.

The image is 60 x 60 and 3/4 of the image is transparent and 1/4 is coloured a green color. When I change the image to a solid color at 60 x 60 (no transparency) and run the app, the line disappears?

Here is my code:

func generateGroundSegment_SingleSegment() {

    nodeSegment = SKSpriteNode()
    nodeSegment.texture = arrayTextureSegment[Int(myElement)]
    nodeSegment.size.width = sizeSegmentWidth
    nodeSegment.size.height = sizeSegmentHeight
    nodeSegment.position.x = countSegmentX * sizeSegmentWidth
    nodeSegment.position.y = (countSegmentY * sizeSegmentHeight) - nodeWaterLayer1_1.size.height - nodeSegment.size.height/2
    nodeSegment.zPosition = 190
    //generateGroundSegment_Type()
    nodeMovingPlatform9.addChild(nodeSegment)

}

The node with the white line is a child to another node which has a zPosition of 0, is coloured clear and is the node that moves to the left. The node that move to the left is a child to one other node, and this node also has a zPosition of 0 and is coloured clear.

Does anybody know what might be causing this? I though maybe the image was trying to resize or something, that is why a specified the nodeSegment width and height. I have other image used, and none of them have the white line appear. All images are 60 x 60.