Jisho

I don't believe that's a mistake. へた definitely is the pronunciation, I believe they're just above the 下 because it's an odd pronunciation for those characters.

へた is the pronunciation for the word as a whole. It's not the reading of either character specifically. There's no particular reason to say that the furigana should be in a particular place, unless you're just bothered by the appearance of it from an alignment perspective.