datetime subject to rounding?

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-10-02.17:01:42.584>
labels = ['3.8', '3.7', 'library', '3.9']
title = 'datetime subject to rounding?'
updated_at = <Date 2021-10-28.22:37:10.910>
user = 'https://github.com/dvarrazzo'

bugs.python.org fields:

activity = <Date 2021-10-28.22:37:10.910>
actor = 'piro'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-10-02.17:01:42.584>
creator = 'piro'
dependencies = []
files = []
hgrepos = []
issue_num = 45347
keywords = []
message_count = 4.0
messages = ['403059', '403062', '403078', '405284']
nosy_count = 4.0
nosy_names = ['rhettinger', 'piro', 'dfortunov', 'ewjoachim']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue45347'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']