OK, then what needs to be confirmed is how net balancer achieves this, it must monitor traffic. The big key is how doe it monitor and throttle this traffic, I suspect it may be through some sort of proxy. If it is then it needs to be coordinated with the web shield proxy by adding that proxy port to the avastUI, Settings, Troubleshooting, Redirect Settings, Web section, HTTP port(s): list and uncheck the Ignore local communication.
Another option might be avastUI, Real-Time Shields, Web Shield, Expert Settings, and check the 'Scan traffic from well-known browser processes only,' option.
I know nothing about the workings of net balancer, so as Bob said the answer would help others and could have saved everyone some time.