Decompiled code compilation error accessing protected members due to unnecessary casting

[LazaroOnline]

Input code

var cat = new Cat();
cat.Test();

public class Cat : Animal
{
	public void Test()
	{
		var n = this._myProtectedField; // Correct way to access, without casting.
		Console.WriteLine("Test: " + n);
	}
}

public abstract class Animal
{
	protected int _myProtectedField = 2;
}

Erroneous output

var n = ((Animal)this)._myProtectedField  // Error: not accessible like this.

Compiler error message:
Cannot access protected member 'Animal ._myProtectedField ' via a qualifier of type 'Animal'; the qualifier must be of type 'Cat' (or derived from it)

Details

Occurs in both the vscode extension and the stand alone app:
ILSpy version 10.0.1.8346+aad16c66e96eb887eb05887d6b5a9e0522637906
icsharpcode.ilspy-vscode v0.24.0