Thought I'd leave my recent experiences regarding my zigbee devices, post C 8 migration, In trying to stabilize things (zigbee devices falling off network, or non responsive).
There are a few things that appear to have improved my stability (this maybe unique to my environment):
1- Stopped a nightly automated HE hub reboot process (Rebooter)
2- Stopped doing device "configure" in my webcore scripts (i thought this initially helped)
3-Stopped doing massive device "refreshes" on all my devices periodically - I thought this helped them stay "awake"
4-Loaded platform .125 - which appears the most stable thus far (fingers crossed)
So items 1-3 actually made things worse rather than to improve.
My setup is far from optimal but its certainly improved.