From the browser console log:
"09:54:32.004 debug http GET[7] -> url: "/ovirt-engine/api/options/UserSessionTimeOutInterval", headers: {"Accept":"application/json","Authorization":"*****","Accept-Language":"en_US","Filter":true} transport.js:74:9"
"09:54:32.141 debug Reducing action: {"type":"SET_USER_SESSION_TIMEOUT_INTERVAL","payload":{"userSessionTimeoutInterval":-1}} utils.js:48:13"
Your engine "UserSessionTimeOutInterval" is set to -1. VM Portal is interpreting this as "auto-logout a second ago" instead of "do not auto-logout".
The simple fix is to set that value to something >0 in your engine configs.