I have the same glitch on my VV2. I had one more pebble to pick up. And it was in the lower right hand part of the screen and my little boy just stayed there with it in his hands and then it vanished.
And believe it or not,it has taken forever to get that last pebble and the last butterfly.
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You cannot do a kindness too soon, for you never know how soon it will be too late.