Until a few months ago, I was using a simple GET call to:

/me?fields=unread_message_count

To occasionally check if there were unread messages in a couple of page inboxes using the relevant access tokens. This seemed to break sometime around October and now the response that comes back from this call just returns the page ID and nothing else, no errors about missing permissions or anything like that.

I hadn't had chance to look into it properly before now, but I cannot find any explanation for why this stopped working. Any advice to fix this would be much appreciated.