NPM Hardware Health on "Node" is Undefined

Hello,

I've seen this question asked with regard to SAM, but not as much with NPM. A few times in the last week, the Hardware Health Status on my core switch has become "undefined." About ten minutes later, all Hardware Health is back up. Looking at the Switch logs and hardware status, I don't see any issues. ICMP and SNMP continue to work perfectly. Has anyone else run into this? I'm starting to think is has more to do with an NPM service/application. Any input is greatly appreciated.

Thanks,

Colin