We don't have a method to disable this.  Microsoft hasn't documented any configuration setting that will do this.  I would expect that the network would need to change so that settings aren't pushed down in the first place.

The customer wants to be able to use his device to connect to the service provider and have access to all the services without using the proxy?  Do I understand correctly? Is someone looking for ways to circumvent security measures?

Yes, that sounds about right.

The customer is capable of using the network without the proxy settings. Connection Manager is setting these proxy settings when they connect to the network

Right now they must manually disable these settings. Can this behavior of automatically populating the proxy settings be prevented?