I think it's just the pic. Usually from one to two weeks with duck eggs, things are very different and confusing looking because of all of the rapid growth going on. A lot of people think they have twins at this stage from it being so confusing looking in there.
After two weeks it starts to...
I'd guess ten days give or take a day based off these new pics. Do you have a pic of the egg in regular light? Just wondering what color/shade it is. Different duck species have different incubation lengths.
It's a bit hard to tell from the pic, can you take a couple candling pics from the fat (air cell) end? Based off the pic for now though, I'd guess around 8-10 days.