Hello,
I don’t see the detection. So, in the webshield “Advanced setting” set in “Action” for “Virus” category to “ask”. Now the avast alert pop-up appear instead of slider. Don’t close the pop-up and go to C:\Windows\temp_avast_\ and there should be some file named <some_name>.unp. Send us (virus@avast.com) this file to analyze and put “False positive” to email subject, please.