I've been all though LR4 and can't find any way to set what you are talking about. Color Noise Detail is set at 50 by default in LR4, but doesn't get applied unless you adjust the Color Noise slider.
A setting of "25" is pretty agressive NR and would make the cat look plastic.
In that case, would you mind publishing the RAW file or sending it to me privately? I've seen correctly exposed ISO 400 files with more visible chroma noise.
OK I uploaded it to MediaFire.
The image does impress for the noise level, if not the subject & comp, but I can't see how I could have inadvertently added noise reduction to it...
This CR2 RAW file was copied directly from the harddrive and not exported from Lightroom.