I can’t seem to edit posts on here, so I just wanted to note there is a typo in my post where $contact['id'] = $contact_id; that is not part of my issue here.
I see that my post got truncated somehow… argh… and I can’t edit it, double arghhh…
The contact is not updated and the response is:
[02-May-2018 19:11:12 UTC] stdClass Object
(
[result_code] => 0
[result_message] => You did not select any lists.
[result_output] => json
[http_code] => 200
[success] => 0
[error] => You did not select any lists.
)
Solved this by getting the full contact object from the contact/list endpoint, capturing the listid parameter, and adding the p[ID] = ID to the $contact before hitting contact/edit. This post was a hint.
It’s strange as I was not updating any custom fields.