Maybe this is a bug.
At the top right there is an icon for rewards, like a present box. First time it was highlihted I clicked on it and it successfully claimed the pending rewards, showing a pop up message indicating it was ok. Next time the icon was highlighted, I went to my steemit account and claimed the rewards. The pending rewards are not shown any more in steemit, but they are shown in chainbb. The icon is not highlighted. When I click ok to claim them, it works for a while and then goes back to the original situation.