The new emails must still be in your VM webmail inbox – if they weren’t Outlook’s IMAP protocol would have deleted them from your Outlook inbox.
If I had that problem, the first thing I’d check is the “Sort” settings in the VM webmail account.
For example if somehow the “Unread” setting has been ticked, then all new messages coming into the webmail inbox would appear at the bottom of the list rather than the top.
The usual settings are “Date” and “Descending” as above.
If that's not the answer, then at the moment I am not sure what to suggest but post back and I’ll think again.