So is this "really" your answer to imap being essentially broken with office 365 for non-m$ users? I am having the same issue after our org migrated over, and this answer simply shows why it was a bad idea to do so. Can you at least fix imap to work as any other imap service (like ours) does?
Make outlook for linux and I might consider it, until then, properly support imap at least and not use broken features as an upsell to outlook.