Yes, I think it is autolayout. In building my views when I have seen the behavior you describe it is because I'm resizing a view that has fairly rigid constraints between its edges and other views. I usually get around it by first updating my constraints to something less restrictive (by deleting or lowering the priority) and then reviewing the constraints once I have resized it.
You may also have success unchecking the options in the When Resizing Views Apply Constraints To...
menu. In the storyboard editor it is in buttons on the lower right and looks like two rectangles (windows) with one smaller than the other.