Issue faking member functions returning by const-value

I have a MS Test project to Test a sample class shown below.

class MyTestClass
{
public:
	const int ReturnInt() const { return -1; }
	double ReturnDouble() const { return -1.0; }
	const double ReturnConstDouble() const { return -1.0; }
};

The above class is tested as shown below.

namespace UnitTest1
{
	TEST_CLASS(Mock_Test)
	{
		TEST_METHOD_CLEANUP(TearDown)
		{
			ISOLATOR_CLEANUP();
		}
		TEST_METHOD(Mock_Trial);
	};
}
void UnitTest1::Mock_Test::Mock_Trial()
{
	MyTestClass* fakeTestClass = FAKE<MyTestClass>();

	WHEN_CALLED(fakeTestClass->ReturnConstInt()).Return(10);
	WHEN_CALLED(fakeTestClass->ReturnDouble()).Return(10.0);
	WHEN_CALLED(fakeTestClass->ReturnConstDouble()).Return(10.0);

	Assert::AreEqual(10, fakeTestClass->ReturnConstInt());
	Assert::AreEqual(10.0, fakeTestClass->ReturnDouble());
	Assert::AreEqual(10.0, fakeTestClass->ReturnConstDouble());
}

In the Asserts done in Mock_Trial(), the Assert for ReturnConstInt and ReturnDouble are fine but Assert for ReturnConstDouble is failing. The fakeTestClass->ReturnConstDouble() is returning 0. Why is this happening?

Visual Studio 2017 version 15.9.25

Isolator++ version 4.1.2.20