Playing around with Berlin 10.1 and discovered what I almost feel is a compiler bug

Playing around with Berlin 10.1 and discovered what I almost feel is a compiler bug

unit Unit3;

interface

uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs;

type
TTestClass = class
public
constructor Create(const aMessage: String);
procedure Proc(const aMessage: String);
function Func(const aMessage: String): Boolean;
end;

TForm3 = class(TForm)
procedure FormCreate(Sender: TObject);
private
fTest: TTestClass;
{ Private declarations }
public
{ Public declarations }
end;

var
Form3: TForm3;

implementation

{$R .dfm}

procedure TForm3.FormCreate(Sender: TObject);
begin
fTest := TTestClass.Create('Create Class');
fTest.Proc('Call proc');
fTest.Func('Call func');
end;

constructor TTestClass.Create
{ (const aMessage: String) This line can be commented out };
begin
ShowMessage(aMessage);
end;

procedure TTestClass.Proc
{ (const aMessage: String) This line can be commented out };
begin
ShowMessage(aMessage);
end;

function TTestClass.Func()
{ (const aMessage: String) This line cannot be commented out *}: Boolean;
begin
Result := True;
ShowMessage(aMessage);
end;

end.

I think it is an error to not have the same signature on class definition and implementation. But it works fine to leave that out. At least a hint!
Also tried the same with Delphi 2007 and the same behaviour.