I assume this is a me only issue since nobody has reported it and its been an issue since the recent upgrade.
When I click Add Comment to post my comment on a news article the screen sort of moves slightly but nothing happens. If I click it again the page loads with Ajax with the loading square box that appears on the top right eventually showing my comment. If I refresh the page I see my comment appearing twice. As a test I clicked once then refreshed the page. My comment wasn't there.
This is happening to all my computers on Chrome but I do sync Chrome across them all so maybe I am syncing this bug on all machines.
Nope, not alone. I just tested from both Firefox and Chrome. It worked normally in FF but in Chrome, like you, I had to click Add Comment twice before the comment would show up. My Chrome build # is 15.0.874.120 m.