No, it’s not normal to have the on-access protection disabled at startup.
But, if you’re just saying it’s shown for a while, some seconds, and then the ‘a’ ball is rotating again, then should be no problem as the drivers and the residents are being loaded at that time. Be sure that you’re protected even with the icon showing that red sign (if it disappeards after that and the ball rotates).

You can check avast logs to see if there is any error or problem listed there.
Welcome to forums 8)