Secure line has nothing to do with this, most people won't have secure line.
These ads/tips are piggybacked on to the auto update notification popup, the problem being if there is an ad attaches it screws up the auto update notification (no update voice-over and popup duration is ignored).
The resolution is to disable the auto update notification avastUI > Settings > Update - scroll down to Update Options and uncheck the 'Show notification box after automatic update.'
Of course you then lose the auto update notification proper also. Depending on OS, you can hover the mouse over the avast tray icon and that will give a tool tip with the avast version and VPS.