tarfile: unexpected IsADirectoryError on extraction

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-05-21.07:13:29.170>
labels = ['3.8', 'type-bug', '3.7']
title = 'tarfile: unexpected IsADirectoryError on extraction'
updated_at = <Date 2019-06-02.22:04:23.111>
user = 'https://github.com/alter-bug-tracer'

bugs.python.org fields:

activity = <Date 2019-06-02.22:04:23.111>
actor = 'mangrisano'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2019-05-21.07:13:29.170>
creator = 'alter-bug-tracer'
dependencies = []
files = ['48341']
hgrepos = []
issue_num = 36986
keywords = []
message_count = 2.0
messages = ['342983', '343005']
nosy_count = 1.0
nosy_names = ['alter-bug-tracer']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue36986'
versions = ['Python 3.6', 'Python 3.7', 'Python 3.8']