After further investigation, I noticed that the filter is working fine; it is the ‘Last Changed’ field that is the culprit. Before it looks like it was keeping track of the last interface change status, but now the ‘Last Change’ field is when the switch last rebooted. As all of the switches have been rebooted over 30 days ago, all interfaces are showing up, even when someone reboots their computer.
This is frustrating…
BTW, it could also be that we upgraded to NCM 6.1, not sure which upgrade broke this.