I have to report that the fix appears to be successful:

>>> print [m.groups() for m in re.finditer(r'(^z*)|(\w+)', 'abc')]
[('', None), (None, 'abc')]
>>> print re.findall(r"(^z*)|(\w+)", "abc")
[('', ''), ('', 'abc')]
>>> print [m.groups() for m in re.finditer(r"(^z*)|(q*)|(\w+)", "abc")]
[('', None, None), (None, None, 'abc'), (None, '', None)]
>>> print re.findall(r"(^z*)|(q*)|(\w+)", "abc")
[('', '', ''), ('', '', 'abc'), ('', '', '')]

The patch is regex_2.6rc2+7.diff.