Nothing to do with Addis Abebba or similar incident in Alexandria many years ago.
I would really like to know what was the airplane configuration by the time they realised it was a wrong signal. The report says 48 seconds, but that height is too low for such short time from platform height...
The ILS glideslope signal was obviously working bad, because you can never have a false glideslope below nominal glideslope, as far as I know. I have had such event myself at home base and we disconnected immediately. It was VMC, however.
GPWS will not warn you in such a case if you configure, until EGPWS TFC function is triggered at about 500 agl or less.
In IMC and with some fatigue, and at night, I would like to think that I would be aware of the wrong capture, but I cannot be sure until I have such a situation...