It’s a known bug and Avast said it would be fixed with Avast release 17.6
The known bug is the shield not always being on when the system starts.
For what’s shown in your video, try the following: Repair Avast:
Control Panel> Program and Features (Add/remove program)>Select Avast> Select Repair. Reboot when completed
https://www.avast.com/faq.php?article=AVKB204

If Repair doesn’t fix the problem, try the following:
Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A