Node discovery not refreshing on a X4 H

I have just come from installing an X4H on a site and the Node list under the “XBee Network” does not refresh properly.

when i select “Clear list before performing refresh” all the nodes in the list are removed but when the list is re-populated nodes that are no longer powered on or in the area are still seen in the list.

the nodes are removed after a reboot.

Any ideas?
Could this be a firmware issue?

This sounds like expected behavior. The stale nodes are likely still in the neighbor tables of the various other valid modules, which is why they continue to show up. This article might give you some ideas:

These might also drop off the network eventually due to child poll timeout, which is 3 * SP * SN time in length. See page 80:

It should be noted that my reply and links are with reference to Zigbee (ZB). I don’t believe a child-poll timeout exists in the other wireless platforms.