Texture mapping emission with GIProbe produces incorrect reflection

[Swivelgames]

Godot version: v3.0.6.stable.official.8314054

OS/device including version: macOS Mojave 10.14.1

Issue description:

When using a texture map in the emissive channel, reflections generated within a GIProbe display incorrectly.

Steps to reproduce:

1. Download and Import the following test project
2. Select the GIProbe
3. Click "Bake GI Probe"
4. Pan the camera to see the incorrect reflection

Minimal reproduction project:
map_emission_test.tar.gz

I noticed this in my own project and, interestingly, was able to reproduce it with the same test project enclosed in #10534

Texture Map Used

[KoBeWi]

Tried in 3.2.2, there's no reflection at all.
In 0287508 this happens...

Not sure what would be the correct behavior though.