2200 feet! My marathon was 650', and it's considered a hillier course, at least for the area. Congratulations on a great run.
13.9 is definitely longer than I'd expect a watch to measure. I measured 26.41 for the marathon. I have seen my watch track jump around a bit if I'm between tall buildings, and maybe yours could do the same if you were in a gorge or heavily treed area that blocks the satellite signal?