Baked lightmap traces a strange glow around some adjacent mesh edges

[rhossack]

Godot version: 3.2

OS/device including version: Windows 10

Issue description:
Here, there are two lights, both on one side of a wall comprised of 6 thin meshes. I would expect the other side of the wall to be dark; instead, it's dark, with streaks of light shining through at some of the seams for no good reason. I zoomed in and made sure that each mesh had a very slight overlap, and used a high-quality ray traced baked lightmap, so I'm not sure what's causing this if not a bug.

Steps to reproduce:

Minimal reproduction project:

[Calinou]

Related to #30929. The lightmapper is undergoing a full rewrite in Godot 4.0.

Could you upload the scene demonstrated in the screenshot, please? This would help while @JFonS tests the new lightmapper he's been working on.

[Calinou]

I'll close this issue as no minimal reproduction project was provided in time. (Either way, this issue can be considered a duplicate of #30929 and the lightmapper will be rewritten very soon.)