A bug has been discovered in Rawstudio 2.0, that disables de-noise when using the “Quick Export” feature. Ordinary “Save As…” and Batch processing is not affected by this bug.
Technically the de-noising is automatically adjusted based on the scaling performed of the image. Due to the order in which the size is set (or rather isn’t set), the de-noising filter thinks the image is scaled to 0%, which completely disables de-noising.
Luckily the next version is right around the corner, and the current development version is quite stable. And since Anders has fixed the daily Ubuntu build system, you can grab a version there, or do the build yourself from SVN if you have that type of skills.
Sorry for the inconvenience.