Insert on conflict do update fails with duplicate rows - there are no duplicates

I managed to replicate the issue with the following data & tables attached
download link.

I am trying to insert from bugtest.temp_on_conflict_test into
bugtest.history, both tables have a primary key on history_id so there
cannot be duplicates

The insert query also uses distinct on (history_id)

INSERT INTO bugtest.history
(account_id,appo_id,account_name,resource_owner_name,resource_owner_id,resource_owner_user_id,resource_id,resource_type,preview,resource_date,history_id)

select distinct on (history_id) * from bugtest.temp_on_conflict_test limit
2
ON CONFLICT (history_id) DO UPDATE SET
account_id = excluded.account_id,
resource_owner_name = excluded.resource_owner_name,
resource_owner_user_id = excluded.resource_owner_user_id,
resource_owner_id = excluded.resource_owner_id,
preview = excluded.preview,
resource_date = excluded.resource_date,
account_name = excluded.account_name
RETURNING *

Reproducible dump:
https://limewire.com/d/2d598eff-f7c9-47d2-80d6-7e522ee1688c#ru2TRVilIqQdqmEjr2-_H4z67PHYe2JZAshDErA8umw