Okay, I noticed this behavior back in Windows 7 (maybe it even did it in Vista, I don't remember).
But on occasion, when a backup job is running (I'm testing Macrium Reflect via the trial), I can see the filesize increment, as if somebody or something is hitting F5 in the display of the backups' target folder.
Other times, I have to repeatedly hit the refresh button or I have to press F5 myself, because the refresh doesn't happen on its own.
Question: I like the auto-refresh. Where can I learn more about it and/or how to turn it on/off for all folders?