Subprocess using list vs string

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-02-20.00:11:43.568>
labels = ['3.8', 'type-bug', '3.7']
title = 'Subprocess using list vs string'
updated_at = <Date 2020-02-20.18:46:18.390>
user = 'https://github.com/nik-sm'

bugs.python.org fields:

activity = <Date 2020-02-20.18:46:18.390>
actor = 'jweese'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2020-02-20.00:11:43.568>
creator = 'nik-sm'
dependencies = []
files = []
hgrepos = []
issue_num = 39692
keywords = []
message_count = 6.0
messages = ['362294', '362323', '362333', '362337', '362340', '362342']
nosy_count = 2.0
nosy_names = ['jweese', 'nik-sm']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39692'
versions = ['Python 3.7', 'Python 3.8']