It says the text is too close to the edge, but what edge is it talking about? The sticker element to the right of it, is lower on the page. If I move that particular text box around, i sometimes still get that little error icon.
Usually they allow for a certain margin around the edge of the page that they can't guarantee they won't cut off. On some services you can click a button to show where it is. The sticker doesn't trigger it because they figure that some people might be OK running that off the edge of the page. But no one wants to lose the bottom edge of their caption to the knife.