TG2 can deal with sand-scale features, but large ranges of scale or small displacement can cause problems in certain circumstances at the moment. I'm guessing that's what's happening here. The problem does occur within a small range of settings and a slight change can mean the difference between a proper render and an example of the bug. But as you are already at such a small size it's hopefully not a big issue that you can't go smaller for now.
- Oshyan