Hello chris, this is the problem i already have reported: “Problems with Zigbee binding since Openhab 2.5.10?”
First all zigbee_routes and neighbours disappear, then the devices go offline after some time. The time depends on the refresh period.
When I restart only OpenHAB (systemctl stop openhab.service and systemctl start openhab.service), the devices are online again. After the Mesh period time the neighbors are filled again.
Even when i disable the CC2531 coordinator and enable it again using the Main UI, the devices are online again.