I think we have nailed down a problem we've been having in the studio where max/corona windows suddenly start flickering on and off and getting focus/no focus, we think it's happening when CoronaAutosave kicks in during a render. It seems not to happen when monitors are off/sleeping so overnight full-res renders are finishing fine and autosaving just fine - but when running a simple mid-res render during the day when monitor is on and UI is showing, we think when autosave kicks in this is when it happens.
Can't verify for sure but pretty sure about this.
max 2018 sp4, Corona 1.7.3, windows 10, various nvidia cards mostly 1080ti