I have not changed the monitor profile in between C1 working, and C1not working.
but maybe you've updated OS X?
I have just looked at the profile (Output / Process recipe / ICC Profile) and i have it set to 'embed camera profile' - however if i change that to any other ICC profile, everything seems to work okay again!
Accordingly i am guessing that means it is not the monitor profile?
now to me this sounds that it is with 99% chance the monitor profile! strange as it sounds...
The input profiles (camera profiles) only contain 1 table (1 output table). So you can not convert into a camera profile (you can try that in Photoshop as well) - you only can assign a camera profile to a file.
The camera profile is assigned to the raw file (in the tool "base characteristics") and if you set the output to "embed camera profile" this command only tell's the software not convert into any other color space, but just to assign the camera profile to the file.
However, of course, C1 by default also translates to the monitor profile at the same time...
Now if you switch the output to another profile I assume C1 is translating directly to that profile (but not to the monitor profile as there is a bug in your case).
So it only seems to work... but most likely you won't see the right colors.
Of course I'm not 100% sure... just an educated guess...
edit: you can also test if it's the monitor profile when you simply set AdobeRGB (or sRGB) as monitor profile in Color Sync. Just for testing of course...
- close C1
- change monitor profile in Color Sync
- start C1, set output to "embed camera profile"
if that works it's the monitor profile...