Check what the Notifications shows for these 12 notifications.
There might be something that requires attention. Perhaps something related to the (!) in the Viruses & Malware section of the scan, even though it indicates 0 Malware threats found. Having checked out the Notifications reply with any information you might thing relevant.
That said there should still a Next and possibly and Ignore button present.
I would suggest closing the windows manually and try an Avast Repair. AvastUI > Menu > Settings > General > Trouble shooting > Repair APP. Restart your system after the Repair and see if that resolves it.
