Black Artifacts Displayed with Lightmap Density View

Hello all -

Hoping someone can help solve a strange behavior I’m seeing. Anytime I am in the “Lightmap Density” optimization view, I get some odd black artifacts showing up overlaid on the mesh with the lightmap density. This happens in a fresh project (using the VR template). Can anyone shed any light on some setting or thing I may have done to break it?

See attached images. Thanks.