Hi
When I try to ping my Xenons from the web console they don’t ping even when the last handshake is shown as few minutes back. Also, some of the blue dots show against devices whose last handshake was few days back.
Seems like the web console and the devices are unusable and still have many issues.
Due to the connectionless nature of the UDP communication of the mesh devices the informative value of that dot is near zero 
I'd say that assertion is not yet backed with evidence.
What code are you running on your devices?
Which gateway are you using?
Which device OS versions?
Is the gateway reachable?
BTW, is this issue different enough from your other one here
The mere inversion of direction does not necessarily warrant the need for a new topic IMO.
This is a different issue.
This issue is there even there if there are eight Xenons in a mesh network.
It’s a known thing about the status “LEDs” in the Console and Web IDE not being reliable, especially for UDP devices. It’s definitely on the list of Things To Address, but my understanding is that it’s a non-trivial thing to improve.
The inability to ping or flash the devices could be due to an issue that was recently discovered where Argons can “breathe cyan” when in fact they’re not really connected to the cloud. The fix for this will be in 0.8.0-rc.28 which should be released in the next couple weeks.
If an Argon gets into this state, any mesh’d Xenons will also merrily breathe cyan. A few details are here.