Any AfterShot Pro + XZ-1 users here?
After some investigation, I think I have some ideas about what is going on. For some reasons, the chroma (color) noise is more pronounced with AfterShot Pro RAW processing (and I do agree with you that ASP's RAW processing is inferior).
I found a workaround in the comment section of this article:
In summary, I downloaded the (free) Wavelet Denoise and Wavelet Sharpening Plug-in for ASP. I have tried both of them before and Wavelet Denoise was initially not very impressive for me. But the denoiser has the ability to denoise luminance and color noise separately. I used a stronger number for color noise and ended up with an acceptable image. Along with RAW Impulse Noise Removal enabled but not the Raw Noise reduction.
The reason I prefer ASP is because it is faster, much faster, than Olympus Viewer. And AFAIK, faster than Lr as well.