Using New Outlook on Windows for personal email, calendar, and contact management
Sorry to hear that you are having this issue. Could you please sign in directly to Yahoo Mail in your web browser and check whether the same messages also appear in the Archive folder there? Also, please clarify whether each affected message appears in both Inbox and Archive at the same time, or whether some messages go only to Inbox while others go only to Archive.
Please also confirm whether the affected emails come from specific senders or whether this happens randomly with different senders, and whether you have the Yahoo account configured on any other mail application or mobile device besides New Outlook for Windows.