HDRP Pixelated Light That Does Not Exist?

Hey all.

Occasionally I see what looks like a weird, pixelated light in my scene with the HDRP. It often occurs on objects that use the default material that is auto-generated when I import an FBX from Blender 2.8. When I replace it with a material that's created in Unity, the glitch goes away.

This time it happened to most of my materials when I updated from 2019.1.0b7 to 2019.1.0b9 and HDRP 5.8.2 to HDRP 5.10.0.

It's a super-weird effect. It follows the camera around. Only affects objects like a couple meters or so away. It looks like a point light that has a pixelated edge. It also only points in the -Z direction...?

This is what it looks like when I push the camera right close to a bluish-grey wall.


The full-sized version has not been upscaled. It was a 2130x701 crop of a 2560x1440 screenshot. The one pixel in the pixelation is actually 16 screen pixels for the top of the brightest circle (as counted in Photoshop).

The question is... ... what is this? Where does that point/spot light effect come from? I'm back on 5.8.2 and it seems to have gone away so I'm good for now (I'm currently making a build to confirm that -- edit: Yup, the corruption is gone in the 5.8.2 build.) but I don't even have the slightest clue what's causing it. Is it just me? Or has someone else seen it?