Melon / Pumpkin crops will attach to their block, even without being fully grown

When planting a pumpkin seed or a melon seed, and placing a pumpkin / melon on the block right next to them, the crop will attach to this block.

What I expected to happen was that the melon / pumpkin would only attach to fully grown crops.

Here is below a proof of what I say, and as you can see, it takes the texture of the fully grown & attached crop, but keeps its color.