Since we started using 6748 and 6724 cards in our 7609's a number of years ago, occasionally we will find that any unoccupied ports will no longer recognize any SFP's. The other occupied ports will continue to function normally.
The only other symptoms are that if I were to take a SFP from a previously used port and try to insert it in one of these "stalled" ports, the router will still see the SN as being still in the SFP's last location. Occasionally I will see an "unrecognized sfp" in the log, as if a non-Cisco sfp was inserted.
We have not been able to identify if a non-Cisco or faulty SFP has been the root cause, and the only resolution is to reseat the card till it happens again.
I have had a TAC case opened on this issue for several months and had no luck in finding a cause.
I am hoping someone else has seen this issue and might be able to point me in the right direction.