Light2D's Mix blend mode with shadows leaves black lines in occluded room with more lights

[KarmyDev]

Tested versions

• Reproducible in: v4.2.2.stable.mono.official [15073af], v4.3.beta1.official [a4f2ea9]

System information

Godot v4.3.beta1 - Linux Mint 21.3 (Virginia) - X11 - Vulkan (Forward+) - dedicated AMD Radeon RX 6600 (RADV NAVI23) () - 12th Gen Intel(R) Core(TM) i5-12400F (12 Threads)

Issue description

When putting a lot of PointLight2Ds in an occluded room, with walls in the middle, choosing Mix blend mode, and enabling shadows for occluder to work, zooming in shows weird black lines:

Changing their shadow filter from none to average shows the artifacts more clearly:

Changing shadow filter smooth doesn't help...

Changing shadow filter color from "black" transparent to "white" transparent seems to ease the effect..
However you can still see the lines there:

Change shadow filter to average from none and you'll see clearly that the artifacts are still there:

Steps to reproduce

Place a lot of PointLight2Ds with Radial texture, Blend mode set to Mix and Shadow enabled in an encapsulated room with occluded walls, and two pillars on the center.

...or download already prepared Minimal reproduction project

Minimal reproduction project (MRP)

LightShadowIssue2D.zip