3D web scene - DEM/Imagery spillover
I'm having an issue with the 3D web scene viewer and my DEM/Imagery textures. In the viewer, the imagery texture seems to "spill over" the DEM, causing a weird stretched look below my scene. However, inside CityEngine this is not visible at all, and I've checked that the DEM file and the imagery file have the exact same extent, so I know that isn't the issue. Is this a bug in the viewer? Anyone have any suggestions on how to fix this? I've tried re-clipping my imagery in a variety of ways but I get the same result regardless. I appreciate any help this community can provide!
I've included screenshots to better explain. The first screenshot is what it looks like once published to a 3D web scene in the browser. 
This is the same model within CityEngine:
