TLS 1.3, client polling returns event without data

GitHub fields:

assignee = 'https://github.com/tiran'
closed_at = None
created_at = <Date 2021-03-25.08:54:27.575>
labels = ['expert-SSL', 'type-bug', '3.8', '3.9', '3.10']
title = 'TLS 1.3, client polling returns event without data'
updated_at = <Date 2021-03-30.09:10:27.346>
user = 'https://bugs.python.org/gchauvel'

bugs.python.org fields:

activity = <Date 2021-03-30.09:10:27.346>
actor = 'gchauvel'
assignee = 'christian.heimes'
closed = False
closed_date = None
closer = None
components = ['SSL']
creation = <Date 2021-03-25.08:54:27.575>
creator = 'gchauvel'
dependencies = []
files = []
hgrepos = []
issue_num = 43622
keywords = []
message_count = 6.0
messages = ['389496', '389497', '389498', '389499', '389807', '389812']
nosy_count = 2.0
nosy_names = ['christian.heimes', 'gchauvel']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue43622'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']