I'm seeing two things happen with it ...
1. Randomly all the graphics will be reversed. The R37 knob will be on the left, and the Limit/Compress Switch will be on the right, and the Gain knob will be on the left, and the Peak Reduction knob will be on the right. As soon as you click anywhere on it, they switch and go in to the correct position.
2. It will randomly not work when inserted in to the Pro Channel. The Gain side will raise and lower the volume, but the Peak Reduction side has no effect, nor does the R37 control. To correct this I'll have to 'replace' it with a different Module, and 'replace' that Module with the PC2A. Sometimes I'll have to do that 5 or 6 times before it will start working.
EDIT: My apologies, I just realized you were talking about the stand alone plug-in. I'm talking about the Pro Channel Module version.
I've used R-Mix in 1 large project and did not see the anomaly you talked about aries. But it drives me crazy that the faders zero out at the top rather than the center.