This information is pulled by SNMP requests.
Are these devices configured as SNMP Device Type in NPM ?
If you run a MIB walk on the OLD-CISCO-MEMORY-MIB on these devices do you get results?
Check all the OIDs that end with *Miss from the above MIB.
Might not be the exact problem, but I've seen this happen to bandwidth reporting numbers when the interface is unabled to be fully polled for whatever reason. The DB inserts '-2' as the value. While the interface shows that it is operational, certain stats can't be "gotten" by Orion. In my case, it was due to polling values and deadlocks in the database, but has since been fixed by modifying the polling intervals.
Thanks for the details.
If you setup a wireshark trace, open the web console, go to Admin > Manage Nodes.
Select your device and click on More Actions > Poll Now.
Do you see it polling the *Miss OIDs ?