layoutto problem

Hi. I'm developing a board game. I use absolutelayout and position the pieces on it using AbsoluteLayout.SetLayoutBounds. For moving the pieces, first a piece should be tapped, then a destination should be tapped, and then when the piece is tapped again it is moved to the destination.
Now the problem:
When I have selected the piece and destination, and then I tap the piece it animates to destination but immediately returns to its original position. Why is that?
I'm using layoutto with await for doing the animation.
thanks.