Photoshop CC2015 has introduced a strange behaviour with the crop tool.
I often use the crop tool in reverse - dragging out wider/taller to add some more canvas to an image. Sometimes I also use the arrow keys to nudge the crop tool's position.
With CC2015 - when nudging I get this weird flickering/bouncing effect where the image is momentarily stretched to the wider/taller crop area and then it bounces back to 100% size. Every arrow nudge causes this bounce to happen.
This is OS X 10.10 specific and I'm aware that there are known video driver issues but this did not happen with CC2014.