And to record the workaround for 3.1 and 3.2 (courtesy of Michael):

Adding a "_super = super" alias at the module level and using the Python 2.x style long form invocation on _super() in affected methods will avoid the compiler games played when using super() directly. That is::

_super = super
class X(object):
    
    def __init__(self):
        _super(self, X).__init__()
    
    @property
    def __class__(self):
        return int
        
print (isinstance(X(), int))