SPECIFICS:
I’ve been building a material using a component mask and a linear color texture node with all 4 channels to switch between varying options for the emissive of my material. The texture in questions is using all 4 channels for different windows that are lit up for a building. Each channel has different windows lit up and the alpha has all windows lit.
THE ACTUAL PROBLEM:
If I plug any channel into the emissive slot directly, everything is fine, but as soon as I use a Component Mask, the Alpha is always blank and gives an error. Is this an engine bug? Seems strange that no one would have reported it by now. I’ve checked this in 4.15 and 4.21 and it happens in both versions.
Here’s a gif showing what happens: