Zoom Panelists Registered then disappear from list on event day - Webinars

Hi All,

We book Panelist links for webinars via API call, which then provides the link back to us.
Recently there has been a really inconvenient issue, where we will check the Panelist names on the UI, all are there, but on the day of the event, at least 1 of the names de-registers. We have no API call setup to run to delete, remove a panelist. It seems to only be happening to the person that will be the moderator for our event (though there is no way to show this in zoom). I'm wondering if this could occur if maybe they try the link early, or anything that may cause an issue for it to be removed?
Has anyone else encountered this at all?
Many thanks in advance!