I don't know about LX7 (it's on it's way to me BTW) but in case of LX5 I can say YES, there are yellow blobs/pattern in dark shots ISO 400 and up. I used only RAW in LX5 so it was not a big issue for me, but in SOOC Jpeg it was unacceptable for me. That's one of the reasons why I sold LX5. Now LX7 has new sensor and new image processor, so it should be blob-free. Yellow cast (as in the picture by tedandtricia) and yellow blobs generated by LX5 sensor are two separate issues. One is WB related, second is sensor/processor related.