Issue with UITextView in an animation block

Question

I'm having an issue with a UITextView inside another UIView whose frame is manipulated in an animation block when the keyboard displays.

During the animation block the UIView scales beautifully and as expected, but the UITextView jumps out of it's superview(the UIView being animated) at the start of the animation. By the end of the animation, the UITextView ends up in the right place... what gives?

Can anybody explain why the UITextView is jumping out of it's container view at the start of the animation?

Thanks in advance.