So, it's still not getting updated, but only on one of the computers.
Does anyone know when this information gets sent, and what application does it? I suspect it could be a firewall setting blocking it, as the other computer that is getting its status updated doesn't have any special firewall (just the built-in Windows firewall). To be clear, Avast IS getting updated with the latest definitions; it's just not being reflected on the My Avast page. I leave the affected computer on all the time, so that's not an issue.