I don't know if commenting will help increase visibility. But I'll comment anyways.
Any use of elemental ward based on emissive color does not work e.g. when subsumed on other frames, it does not work. On Chroma if you subsume over Spectral Scream, it also does not work.
The tooltip only shows heat, but otherwise functions normally on Chroma as long as you leave his Spectral Scream alone.