Runtime Virtual Texture normal shimmering (between mips?)

Using RVTs to make roads in UE4 terrain. I’ve not been able to solve this flickering/shimmering issue that occurs when noise or horizontal lines are perpendicular to the sun direction in the normal map. Driving me crazy! Would much appreciate any ideas about what the source of this problem could be.

It appears to happen between mips, as when I move along the road it maintains a consistent distance from the camera. No setting I’ve been able to change on the normal texture, on the runtime virtual texture, or the RVT sample node has had any effect. It also isn’t related to the material as even the simplest material produces this issue. Are there any configuration settings I could mess with to alleviate this?