Lumen Translucency lighting vs opaque mismatch is larger than expected

The licensee's VFX team has been struggling with getting their Niagara systems with translucent materials to fit into the environments they are being used in. In a project with default settings, they were able to recreate a test scene where an opaque material had a pretty significant lighting mismatch compared to a translucent material with an opacity of 1. They would never really expect them to perfectly match, but this difference is notable enough that I wanted to raise a ticket here. They wanted to ask is this much disparity expected?

Steps to Reproduce

1. Open the attached repro project
2. Observe the lighting differences between the two being fairly significant, even when moving the spheres closer to the surface