The popup is actually meant to be the auto update notification (check your avastUI > Settings > Update and you will see that an auto update has just taken place. It appears that these tips/ad popups are piggybacked onto the auto update notification popup and this looks like it messes up the display and sound for the auto update notifications.

Unchecking the “show social networking features” as suggested won’t work as they are piggybacked to the auto update notifications. The only way to get rid of them would be to uncheck the auto update notifications, reducing the duration of the popups won’t work either as it doesn’t appear to work as it used to (so another bug).