zoneinfo gives incorrect dst() in Pacific/Rarotonga between 1978 and 1991

GitHub fields:

assignee = 'https://github.com/pganssle'
closed_at = None
created_at = <Date 2020-06-09.20:09:18.023>
labels = ['type-bug', 'library', '3.9', '3.10']
title = 'zoneinfo gives incorrect dst() in Pacific/Rarotonga between 1978 and 1991'
updated_at = <Date 2020-06-09.20:09:18.023>
user = 'https://github.com/pganssle'

bugs.python.org fields:

activity = <Date 2020-06-09.20:09:18.023>
actor = 'p-ganssle'
assignee = 'p-ganssle'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-06-09.20:09:18.023>
creator = 'p-ganssle'
dependencies = []
files = []
hgrepos = []
issue_num = 40930
keywords = []
message_count = 1.0
messages = ['371136']
nosy_count = 1.0
nosy_names = ['p-ganssle']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40930'
versions = ['Python 3.9', 'Python 3.10']