This is not happening when landing, but when you fly fast and low, like 30ft AGL. Hence why I'm saying that it's not a bug, but probably more of a thing that the devs didn't get to yet.
You can try it yourself, it's very easy to reproduce. Just take your -18 and go MIL over the water or somewhere else flat enough to get really low, and see what happens when you get low enough. :)