I use the animations sample from the telerik app, to pick/select some images in the same way (Grid with Images in the 'First look' animations sample).
I notice after the last update, my app, after you tapping the image the animation stop or never start.
I check the telerik sample and the same results (before the animation only stop if you tap the tile again)
private RadAnimation CreateUnselectedAnimation()
RadScaleAnimation result = new RadScaleAnimation();
result.StartScaleX = 0.9;
result.EndScaleX = 1.0;
result.StartScaleY = 0.9;
result.EndScaleY = 1.0;
result.Duration = new Duration(TimeSpan.FromSeconds(0.4));
result.AutoReverse = true;
result.FillBehavior = AnimationFillBehavior.Stop;
result.RepeatBehavior = RepeatBehavior.Forever;
Did something changed ?