Hm, I have seen this as well. Invisible mode isn't something I would necessarily like for anyone other than staff, who I think can already do it.
Is this a site wide issue showing people offline or just me?

In the game it showsyou as being online.
Meaning that the reason 'mobile device' is out of the question
try a few things and we find out.
By the way good match ;)

i have noticed players appearing as offline and moving like they are online. Is there an "appear offline" mode?
me too... some players appear offline, but they are able to make a move in Correspondence chess

So the test is done and we exclude the mobile device being the reason.
Lets hope the issue is handled also by the techteam, is there a 'ticket' started by the techteam ?
Okay, challenge me Donna and i will tell the status during the challenge and during the game.
If you want, of course
I noticed the sudden moves without online signals also! For the gameplay i don't mind, but it is nice to see when someone is indeed online or not.
What i also noticed that there are three different situation with the online symbol.
- no symbol (offline)
- symbol blinking (online)
- symbol static (not sure)
Maybe within that lays the answer.