Thanks Richard,
I have verified that this counter - cieIfInGiantsErrs is not really an error in my case.
This displays the same as data as:
"show counters interface <interface>"
or
"show interface <interface> counters errors"
What this counter shows is any octets exceeding 1518 bytes.
Since we have the MTU set to 9216, any jumbo frame will increment this counter, even if they are valid frames below the MTU size set on the interface.
Back to the thread title, this is still worthwhile monitoring for any interfaces with the default MTU set (1518) to highlight potential problems of oversize frames being received.
Art