If you’re seeing the above error after running a person merge overnight, run the script below and enter the Person ID of the source person in the merge. Once that’s done, retry the merge.
update chronology_finished_events
set event_date_order = 0
where person_chronology_id in (
select
pc.id
from
person_chronologies pc
where
pc.person_id = <person_id>
and
pc.finished = 'Y'
)
and event_date_order is null;