multiprocessing creates duplicates of .pyc files

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-02-29.12:05:59.465>
labels = ['3.8', 'type-bug', 'library']
title = 'multiprocessing creates duplicates of .pyc files'
updated_at = <Date 2020-02-29.12:05:59.465>
user = 'https://bugs.python.org/ivb'

bugs.python.org fields:

activity = <Date 2020-02-29.12:05:59.465>
actor = 'ivb'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-02-29.12:05:59.465>
creator = 'ivb'
dependencies = []
files = []
hgrepos = []
issue_num = 39795
keywords = []
message_count = 1.0
messages = ['362974']
nosy_count = 1.0
nosy_names = ['ivb']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39795'
versions = ['Python 3.8']