Is there are change to the AV Enginge.
Since Aug 12th all of our Proxies did not detect any "McAfeeGW: Potentially Unwanted Program" anymore?
We did not change our AV setting for month....
i think the best way will be to submit a ticket to Avert team to check this.
Btw, have you changed any other filters like URL filter, URL Reputation and so on. Perhaps other filters are blocking malicious requests and therefore there is nothing to scan for GAM?
I'd suggest checking your update logs. The new AV engine has been a slow phased roll out.
You may have just been at the tail end of it.
Please also let us know what version you are running, I know in 7.4.2 there were changes surrounding PUPs detection that may now be reflected in the engine update.