Why you would even want to run this off the wall scan with No Action for everything is beyond me.
It may well be beyond the logic of the avast too so it overrides the do nothing and sends to the chest, which kind of negates the whole point of doing a scan.
If you actually read the help file, leaving the Automatically ‘apply actions during scan (check this box to select an action)’ blank actually means No Action, so I see zero point in checking this box and then setting everything to No Action, when that is the default action when unchecked.
Does the window say that file has already been moved to Chest, or does it just offer you the action - if you click “Apply”? If it’s the later, then it’s OK.