Quick update, last month I worked with a Plex team member to retrieve some more info + logs and everything was forwarded to the server development team. With the holiday period I don’t think much has happened yet but as soon as I hear something I’ll let you know.
Temporary solution, working for me:
Rolled back to version v1.22.3.4523 which worked, all channels found. After updating back to the latest stable, the channels are still there but obviously this isn’t a solution. At least for me no longer a problem right now.