Trashed mail coming back into inbox

Hey there! It sounds like you're facing an annoying issue with your Yahoo Mail in the Mail app on your Mac. I understand how frustrating that can be. It's strange that only the trashed mail from your Yahoo account is returning to your inbox, while other email accounts are working fine.

One thing you could try is checking your Mail settings for your Yahoo account. Make sure that the "Move deleted messages to the Trash mailbox" option is selected. To do this, go to Mail > Preferences > Accounts, select your Yahoo account, and click on the "Mailbox Behaviors" tab.

If that doesn't solve the problem, it might be worth removing and re-adding your Yahoo account in the Mail app. This can sometimes fix syncing issues. To do this, go to Mail > Preferences > Accounts, select your Yahoo account, and click on the "-" button to remove it. Then click on the "+" button to add it back and reconfigure the account.

If the issue persists even after trying these steps, you could consider reaching out to Yahoo Mail support for further assistance. They might be able to provide more specific troubleshooting steps based on your account and the Mail app version you're using.