I was experiencing unintended network bandwidth throttling with a Win10 guest OS. Even though the "Network Conditioner" setting was unchecked I was seeing about 3Mbps data rates on a 1000baseT local network. When I checked the Network Conditioner box but left the Profile at "Custom" which should leave the bandwidth at maximum, my network speed was restored to full.
So this appears to be a bug in the network setting.
So this appears to be a bug in the network setting.