Microsoft Account (Teams and Outlook) accepting login for one account but logging into a different account

We have been having consistent security problems with Microsoft Accounts which I will describe below. These all happen on the company's owned computers and network. * A user logs into their company Outlook account from the web-based login page but then Microsoft takes them to a different user's account from the same company. * Similar to case 1 above except the user is logging into their account on the Microsoft Team's desktop app (they log in with their account credentials but are taken to another users account). * A user cannot log out of their Microsoft Team's account. Upon clicking the logout button, Teams shuts down but then promptly restarts automatically and is still logged in to the original user's account, this persists even after a full computer shutdown. My company has had this problem for over a year, and it has gotten progressively worse. What might be the source of this problem?
http://dlvr.it/S0H40P