LightmapGI only works on Forward+ Renderer, but doesn't work on Forward Mobile Renderer and Compability Renderer

[YuWongXX]

Tested versions

4.3 stable

Issue description

GIProbe (for dynamic objects, of course) only works on Forward+ and even Compability Renderer, but doesn't work on Forward Mobile Renderer.
The thing is that the document doesn't mention that mobile doesn't support lightprobeGI. And even the lower end Compability Renderer works well. So I assume this is a bug.

Even the lightmap itself, it flashes on Forward Mobile Renderer, but the problem dissapear on Forward+ and Compability Renderer.

Minimal reproduction project (MRP)

GIProbe BUG.zip

[YuWongXX]

I also find that LightmapGI is overall buggy only in Mobile Renderer

[clayjohn]

This is expected. VoxelGi is a Forward+ only feature.

See the documentation of VoxelGi https://docs.godotengine.org/en/latest/classes/class_voxelgi.html#description

[AThousandShips]

This is not about VoxelGI but LigthmapGI though

[akien-mga]

This is not about VoxelGI but LigthmapGI though

Confirmed by checking the MRP. The OP got the terms confused though and referred to GIProbe, which is the 3.x name of VoxelGI. But indeed the MRP is only using LightmapGI.

[Calinou]

Thanks for the report! Consolidating in #84846.

[YuWongXX]

After struggling a few days, I'm sure this is a bug.