[c-nsp] "show idprom int TeX/Y" stops working on sup720?

[Phil Mayers]

All,

One of our Sup720 appears at some point recently to have started 
refusing commands like:

ac-core#sh idprom interface te1/1
Unable to retrieve idprom information

This is module-specific - it fails on slot 1 (6716) but works on slot 2 
(6704).

Other boxes with the same IOS and modules work just fine.

Any idea what might cause this? Any way to fix it without reloading the box?

Cheers,
Phil