"New Outlook" preview inbox doesn't refresh

I've been using the new Outlook preview (the one you enable by toggling the "Try the new Outlook" switch in the main Outlook app for Windows) and I love it. It's so much faster than the main version.

Unfortunately, a few weeks ago I noticed that the inbox had stopped updating automatically. I still get notifications that new messages have arrived, and the icon in the task bar indicates that I have unread messages, but when I look at the Outlook window the inbox shows no new messages. I have to click on a different folder and back to the inbox for it to refresh and show the new emails.

Obviously this make the product basically unusable - I can't afford to risk missing important emails - so I keep switching back to the main Outlook app, each time giving feedback about the problem. Every week or so I switch back to the new Outlook in the hope that the issue has been fixed, but so far it hasn't.

This seems like such a fundamental problem that I can't believe it hasn't been fixed, which makes me wonder whether I'm alone in having this issue. I'm using a work account with Outlook and, to be clear, I don't experience the same issue when I'm using the main Outlook app.

Is anybody else having this problem? Is there anything I can do to fix it or is it a problem with the app itself?