I have just played the level # 856. The only 3 choices of Friends I had were Olivia, Misty and Odus I have not received the BGT as one of the options.
I tried 5 times by loosing and winning the level, and the board did not get stuck!! So, I would recommend you to play the level with above specified friends -- preferably Olivia. If you do not have her, opt for Misty or Odus and see if you can finish the level without any interruptions!!
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Talk to you soon! Have a nice rest of the day/evening!