No message for badly styled __init__ method arguments

[lcerman]

Steps to reproduce

1. create file foo_bar.py:

class FooBar:
    def __init__(self, fooBar):
        self._foo_bar = fooBar

    def foo_bar(self, foo_bar_arg):
        print(self._foo_bar + foo_bar_arg)

    def bar_bar(self, foo_bar_arg):
        print(self._foo_bar + foo_bar_arg)

2. Run: pylint foo_bar

Current behavior

No complaints about the fooBar argument (should be snake_case).

Expected behavior

Issues a message that fooBar is not in snake_case style.

The following example issues correctly foo_bar.py:6:4: C0103: Argument name "fooBarArg" doesn't conform to snake_case naming style (invalid-name) for the foo_bar method, but not for the __init__ method.

class FooBar:
    def __init__(self, fooBar):
        self._foo_bar = fooBar

    def foo_bar(self, fooBarArg):
        print(self._foo_bar + fooBarArg)

    def bar_bar(self, foo_bar_arg):
        print(self._foo_bar + foo_bar_arg)

Edit: it does so with the default settings and with my custom settings with I have added as attachement.
pylintrc.txt

pylint --version output

pylint 2.5.2
astroid 2.4.1
Python 3.6.8 (default, Jan 14 2019, 11:02:34)
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]]