[smw]

Is this occurring with new annotations, or just old ones? I'm assuming you are on v4.0.3, correct?

Yes, this is on 4.0.3.

So far I've only seen this with annotations created before 4.0.3, but I'll try deleting this one and recreating it to see what happens. I'll report the result here either way.

For what it's worth this doesn't look like a scaling issue exactly. First, because it only affects text annotations, and secondly because the text itself is rendered at exactly the right size; the problem is that the background of the text box extends considerably lower than it should -- and the extra extension is always below the text box, never in any other direction.