Repairing Zigbee Mesh

I am trying to understand what may have caused my zigbee mesh to go haywire yesterday, after almost a year free of major incidents. I didn’t introduce new devices to my network of any kind. I did notice that a not used presence sensor got included automatically, which I thought was strange but not unheard of. Between yesterday and today, almost 80% of my sensors and bulbs dropped out , and those that are still connected are either extremely slow or sending wrong messages. Could this be a local issue in my home or something that may have happened on ST side? I did restart my hub twice in my attempt to ‘fix’ the erroneous messages I was getting from a presence sensor that is in my car. Also, I did open a ticket and am waiting for support to get back to me.