lokesen - believe it or not, this example is actually working normally and is not a bug.
Obviously, the Tiled Background object wraps its texture, so if you enlarge it the image repeats throughout. However, if the object is sized 32x32 with a 32x32 image, and you zoom in a little (in this case using fullscreen mode), it actually does a tiny bit of wrapping round to the other side of the image at the edges. Imagine the image is still tiled in those directions, just you can't see them because they're outside the bounds of the object. So in this case one edge is black and the rest is brown; the side opposite the black edge will still wrap across to the black-edged side ever so slightly, and this creates a visible seam. It's enough to still seam when pixel rounding and point sampling are on. This is just how computer graphics works and would happen with any tool or framework.
The workaround: add an extra row of pixels to the image, or resize the image ever so slightly smaller. For example, make the image 32x33 to add an extra row of pixels along the bottom, and make them the same color. Or, just resize the Tiled Background to be e.g. 64x31, so the last row of pixels doesn't wrap around. Or, just position the other backgrounds to slightly overlap and hide the seams.