Isolator swapping all log4net ILogs with mocks

Hello,

We use log4net in various classes for logging, where our loggers are statically initialized like so:

public class MyClass 
{
    private static ILog _log = LogManager.GetLogger(typeof(MyClass));
}

We noticed that when using Isolator to mock certain classes and method calls, all the ILog instances are substituted with mock implementations, even though non of our test code specifies as such when using Isolator. As a result, many of our tests fail because Isolator is throwing exceptions stating "Unexpected call to ILog.IsDebugEnabled", etc.

It is even more of a problem because we use 3rd party libraries like NHibernate that also leverage log4net, and it's causing exceptions there too because the ILog instances there have been substituted with mocks.

Is Isolator automatically mocking private static fields of classes? Is there any way to turn this off, or perhaps instruct Isolator to call the original log4net method implementation?