Hi tiger2wander,
The decision to block unblock a particular url or domain or IP lies entirely by the members of the avast av solution team.
We here are no part of it and have no influence further than reporting issues to virus AT avast dot com, and what the avast team does with this information is just their privilege period.
If the detection is a false positive it will be dealt with in some coming update. They won't comment directly, but they are known to react quite soon, also avast webshield and networkshield detection is known to be solid state and highly reliable. But you know the status of a wbesite can change within seconds from with active malware as to cleansed from malware or malware response dead...
Some potentially suspicious flags from quttera's and other scanners should be taken like for instance the flags that jsunpack sometimes produces on anomalies or delayed handling of some javascript code also will produce a "suspicious" there. Also benevolent obfuscation could lead to FPs.
This could also mean a bug, a time out, due to a misconfiguration and will not mean immediately it is malcode per se, so not being malcious or not even unwanted code. Do not read more into "code hick-ups" as should as I produce these scan results just for evaluation purposes,
polonus