Why would bounce processing put all emails into CiviCRM.ignore mailbox?
It looks like CiviCRM uses the domain specified in the bounce mailbox settings to generate a regex to match incoming bounce messages.

From the info in your question, I suspect CiviCRM is directing bounces to a (subtly) different domain name. As a result, it doesn't think the bounces are intended for CiviCRM to process, and moves them to the ignored folder (as CiviCRM would with other "not for me" email).

See your mail account settings (Admin > CiviMail > Mail Accounts).

Try ensuring both the return address and site domain match, and see if the problem persists.

Once correctly configured (or, temporarily misconfigured to match the misspelled inbound address!), you can move those messages back from the CiviCRM.ignored mailbox to the INBOX, and re-process them.