Is it like that with all your OPs, just certain ones, or after you've already been to a few? Sometimes it helps to reload the game after every 5-10 OPs.
Other than that, you can try clearing your cache. Maybe try a different browser. Or maybe try restarting you computer. Lastly, you can try posting this in the bugs section of the BYM forum. Sorry, I couldn't be more of a help.