Well, an update on this issue. It wasn't No Render that was the problem. I guess I got tangled up in exporting gmt files and publishing scn files, and not fully checking results. The issue is actually due to the size of the shadow casting mesh. I've split and simplified it into sunrise and sunset meshes, so they're both smaller than the original mesh. And, regardless of the state of No Render, the shadows now draw properly again. So, I'll also be keeping track of the size of my shadow casting meshes in future.