After a day and a half of struggling with “Change of focus disconnections in Rivals matches,” and repeated issues with screen focus changing on Squad battles and having to re-click on the game screen with my mouse, I was able to determine an issue with installed EA Orgin games while playing FUT20. First it was FUT19 seemed to constantly launch without my asking, then BF5, then BF1. After uninstalling everything EA/Origin, except FIFA UT 20, I now have zero disconnect issues due to Origing launching stuff on its own and taking away focus. Hope this helps save others some time and hassles!