Network monitoring not working when ZScaler Internet Security is active

When using QNetworkAccessManager::get() (or similar methods) when Zscaler Internet Security is active, the following warning is shown:

qt.network.monitor: Could not get the INetworkConnection instance for the adapter GUID

indicating that this connection cannot be monitored. Further analysis suggests that Zscaler Internet Security might be using a virtual network adapter with a GUID different to the GUID of the physical adapter, therefore QNetworkConnectionEvents::getNetworkConnectionFromAdapterGuid() fails to find the connection because it seems to always use the physical adapter's GUID.

There are discussions on the web (e. g. https://github.com/ModOrganizer2/modorganizer/issues/1326) that indicate this problem can also happen with other VPN solutions and is not restricted to Zscaler only.