yup, happened to me once but refreshing the page solved it I think.
Pawn Promotion Bug
BJH2013- Do you not get the promotion options, or are you clicking on one of the options and then your pawn disappears? Have you tried a cache clear to see if that helps at all?
I had this same problem. As you can see I ran out of time trying to promote. The rook just wouldn't cut it. Here is a screenshot:

To Dorsiguer,
This is pure curiosity on my part. I noticed that despite your running into the bug you won by checkmate. Any ideas how that happened?
To Dorsiguer,
This is pure curiosity on my part. I noticed that despite your running into the bug you won by checkmate. Any ideas how that happened?
He just said, he was able to promote to a rook. A R+K vs K is an easy win.
The move list in the screenshot seems to suggest that he never got the chance to promote the pawn at all.
[EDIT] I found the game and I see that you were right and R+K vs K is how it ended. I was confused by the screenshot. Curiosity sated. Thanks.
HELP OMG THIS IS PISSING ME OFF, IT RUINED MY GAME!
http://www.youtube.com/watch?v=3x5zY_q1DhU&feature=youtu.be
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While trying to promote a pawn I got this bug:
I can tell you how to reproduce this bug.
The square where white King appears is the square he actuall was.
To get this bug, click on any piece that stands in one of those promotion squares (ie e3 as black) and then move your pawn to the promotion, the piece you've clicked will stand in front of the promotion piece, in this case where the queen should be.
The problem about this is that now you can't promote to that specific piece.
If my instructions were not clear enough please let me know.
P.S.- Hopefully a rook was enough to win the game, but opponent flamed as he thought I was trolling.