GstColorBalanceChannel is not a GstObject derived object but it is wrapped as such in gst-python.
The segfault can be reproduced with the following three lines:

>>> import gst
>>> pipeline = gst.parse_launch("videotestsrc ! videobalance name=Balance ! fakesink")
>>> balance = pipeline.get_by_name("Balance")
>>> balance.list_colorbalance_channels()
__main__:1: Warning: invalid cast from `GstColorBalanceChannel' to `GstObject'
Segmentation fault