There are many bugs in Marsyas (far too many to list here!), but there are a few issues which are more fundamental. We list these issues here, along with workarounds.
Due to the way that observations behave in Marsyas, in some cases it is impossible to differentiate between a stereo signal and a mono signal which is twice as long. In particular, there is currently no direct way to tell apart a stereo pair of spectrums from a mono spectrum with twice the number of bins.
In these cases, we recommend that you use a Parallel Composite: split the stereo signal into separate mono dataflows (using Parallel), then treat each mono signal individually.