The current version of Syck, and related wrapper packages like syck-python and syck-php, use syck 0.55. This version is quite old and has numerous bugs. The current version is 0.61 (syck's svn repository gets updated far more often than the website). Could someone please update these packages?
Also, the current syck-python package may be using Syck's python wrapper, which is nearly unusable. It only includes load(), not dump(), and even that doesn't work very well. I recommend http://pyyaml.org/wiki/PySyck be used instead.