For months now I've seen a height issue on the comment form box in Jetpack Comments when the box is in a collapsed state. The placeholder text, "Enter your comment here" is cut off. I see this all over the web.
Since the box is in an iframe, I don't see a decent way of targeting it with CSS. The problem is on the #comment textarea element, which is getting an inline style of
height: 10px applied to it. In every case I've seen this, doubling the height to 20px fixes it perfectly.