Possible misunderstanding of how `cause` interacts with context manager silencing in python 3

gistfile1.txt

>>> class FalseContext(object):
...     def __enter__(self):
...         l.append('i')
...         return self
...     def __exit__(self, exc_type, exc_val, exc_tb):
...         l.append('o')
...         return False
... 
>>> class TrueContext(object):
...     def __enter__(self):
...         l.append('i')
...         return self
...     def __exit__(self, exc_type, exc_val, exc_tb):
...         l.append('o')
...         return True
... 
>>> with TrueContext():
...     raise Exception
... 
>>> with FalseContext():
...     raise Exception
... 
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
Exception
>>> with TrueContext():
...     raise Exception from ValueError
... 
>>> with FalseContext():
...     raise Exception from ValueError
... 
ValueError

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
Exception