New Outlook auto-deletes Emails in Inbox when they are closed (MacOS)

If I close an email that I'm reading from my inbox, Outlook will auto-delete the email ON OCCASION. There is no rhyme or reason to its method, it occasionally just auto-deletes my email and I have to go and fish it out of the delete box (assuming I notice it). It's amazingly annoying and has caused multiple problems, but microsoft ignores my emails about it (they're probably auto-deleting). 

UNDO does not bring the email back, so it is not a user action. There is a fundamental problem with the coding in MacOS Outlook. HOW CAN THIS GET FIXED before something seriously detrimental happens to my business?