As you can see, the Prepass Dynamic and Basepass Dynamic are off the charts. It only seems to happen when I’m looking at trees; the more trees, the more it happens.
Steps I’ve taken with no luck:
Reduced resolution
Turned off all lighting
Turned off all shadows, including shadows inside every LOD of every foliage mesh
None of the view modes helped identify the problem, but it turned out to be that one of the foliage meshes had “auto compute LOD distance” unchecked; therefore it was rendering on LOD0 like 15k vertices for over 1,000 HISM actors, heh.