It's not that Avast is blocking it completely, try disabling the behavior shield, but leave the rest as is,,,,I had the same problem with the Microsoft Office templates, the behavior shield wouldn't let Office download the templates, even if I added all the office exe files to the exclusion lists globally and within behavior shield, the shield still blocked access to the templates unless I disabled behavior shield.
I have already sent a report to the support team and they are currently working on a solution.