G1000 no 3 letter identifier on ILS. Why?

The other day I flew an ILS into KCNO. The G1000 did not decode the Morse
code and the 3 letter identifier did not appear. I was not in IMC and I did
not manually listen to the Morse code. The ATIS did not indicate a problem.
The localizer and glide slope appeared good. My question. What are some of
the reasons to explain why I did not receive a 3 letter code? In actual IMC,
if I did not receive a 3 letter code, I would have manually checked the
Morse code. I know some probably always manually check the Morse code. Any
comments are appreciated.