It's possible to fix and test fly a GS in less than 3 days.
A notam would have been out in that time, and should be easy to track down.
I'm not saying it happened, but it's possible.
It's more probable though, that if no error was found on the GS monitor, the techs declared it serviceable on the spot.
On a more general note, intermittent failures in navaids/radar/com are a pain. You can change components, calibrate and monitor test transmissions all you want, only to have them fail on you one week after the test flights OK them.
