Chubgraphs (and ChuGens) don't support stereo operation at this time. Its
something we've thought a lot about, but wanted to focus on getting mono
operation right before venturing into stereo/multichannel. Thanks for
bringing this issue up though.
For what its worth Chugins do support arbitrary numbers of I/O channels, but
of course requires implementation in C++.
From an email thread:
Added as an issue here for tracking purposes.