It seems that people get more popups in the early stages of avast free usage.

I have been using avast free for over eleven years, I don’t get an ad/popup every day, but some days I will get two. It takes me a second or two to close the window.

There are times when it is a pain, but I have a high aggravation threshold and I’m not a gamer, but then again if gamers are using silent/gaming mode the popup should be suppressed.

The popup is usually delivered (piggy backed) when you actually get the auto virus definitions update. You will notice that there is no Update popup duration option in the UI as update notifications popup is no longer displayed. So none of those durations are applicable to these popups.