I am generating 2' contours made from a smoothed DEM that is 3.2808 foot (1m) horizontal resolution. The result shows these odd squares that are about 80' on a side. The smoothing was done using 8 neighbors (EDIT: I thought I used focal majority but I checked my notes and I actually did use a Focal Mean. I was also wrong about the 8 neighbors. It was a 9x9 neighborhood.). The DEM doesn't show these squares (see second screenshot below).
I drew one of the squares with the drawing tool to demonstrate, but I think they are pretty obvious.
Q) Can anyone provide any explanation for this, or a potential solution?
This result is from the "Contour" tool in "Spatial Analyst Tools -> Surface -> Contour" and I'm using 10.3.1